Knowledge
Transfer
Network
UK Sensing
technologies for
contamination
in food
Knowle
Transfe
Networ
CONTENTS
TABLE OF
CONTENTS
3
Overview
introduction
Food and drink contamination Contaminated Products Types of physical contamination
HACCP Recent High Profile Incidents
Report objectives
Primary Objective
Secondary Objective
Challenges
Methodology
Current Detection Approaches
Current approaches
Electromagnetic spectrum
On-line Techniques
X-ray imaging
X-ray spectroscopy
Raman spectroscopy
Visual Inspection
Infrared techniques
Hyperspectral imaging
Optical sorting
Terahertz imaging
Microwave detection
Ultrasound
Magnetic Separation
Metal detection
Sampling
Electrical impedance Off-line / Lab-based Techniques
Biosensors Nuclear magnetic resonance Microscopy
Mass spectrometry
Chromatography
Polymerase Chain Reaction
Enzyme-linked immunisorbent assay
ATP Bioluminescence
Technology Summary Table
Challenges
1. The detection of glass fragments
– in particulate food Background
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The Knowledge Transfer Network: Food Sensing Report
4
UK SENSING TECHNOLOGIES FOR CONTAMINATION IN FOOD
Current situation
Manufacturers perspective
Contaminant Characteristics
Potential for innovation
2. The detection of glass fragments – liquids in glass
Background
Current situation
Manufacturers perspective
Contaminant Characteristics
Potential for innovation
3. The detection of plastic
Background
Current situation
Manufacturers perspective
Contaminant Characteristics
Potential for innovation
4. The detection and sensing of fat and gristle
Background
Current situation
Manufacturers perspective
Contaminant Characteristics
Potential for innovation
5. The detection of bone in meat and poultry products
and in fish
Background
Current situation
Manufacturers perspective
Contaminant Characteristics
Potential for innovation
6. The detection of insects in fruits and vegetables
Background
Current situation
Manufacturers perspective
Contaminant Characteristics
Potential for innovation
7. The quantification of ripeness in fruit
Background
Manufacturers perspective
Contaminant Characteristics
Potential for innovation
8. The detection of damage and mould in fruits and
vegetables
Background
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CONTENTS
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Current situation
Manufacturers perspective
Contaminant Characteristics
Potential for innovation
9. The identification of the wrong product in a package
Background
Current situation
Manufacturers perspective
Potential for innovation
10. The detection of “natural plant materials”
Background
Current situation
Manufacturers perspective
Contaminant Characteristics
Potential for innovation
11. Hair and fibre contamination
Background
Current situation
Contaminant Characteristics
Potential for innovation
12. The detection of metal of any sort of food product
Background
Current situation
Contaminant Characteristics
Potential for innovation
Conclusions
Non-commercial / emergent technologies:
Ready in linked sectors
Barriers to innovation
Appendix 1. UK capabilities in highlighted areas
Guide to the Research Councils
Terahertz
Hyperspectral
Capacitance and electrical impedance tomography
Biosensors
Ultrasonic
Infra-red Techniques
Raman Appendix 2: Inputs into the February Workshop
Appendix 3: Acronyms
About The Knowledge Transfer Network
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The Knowledge Transfer Network: Food Sensing Report
OTHER
19%
STONE
RUBBER
3%
1%
GLASS
9%
ANIMAL
FOREIGN
OBJECTS
IN FOOD
(2012)
METAL
32%
3%
PLASTIC
8%
AIOLN
INC
AT
THE
TH
WOOD
3%
E OEFD
AUS
T
C
O
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S S REP R
AIOLN
INC
S
T
A
Y
PH AMI
HE
T
S
I
CON
421
T
H
T
7
FOOD INCIDENTS
REPORTED TO
THE FSA
E OEFD
AUS
C
RT
O
T
GES S REP
A
E FS
H
T
TO
LACRIDENT
IN
1604
or
ct
se
ch
ea
in
th
wi
l
Activity levewith relevance
compared or
to that sect
HIGH
MEDI
LOW UM
2012 2000
THE
21%
FSA
ACTIVITY
RELEVANCE
T
PESTS
TERAHERTZ
ULTRASONIC
HYPERSPECTRAL
INFRARED
RAMAN
TECHNIQUES
CAPACITANCE/
IMPEDANCE
TOMOGRAPHY
BIOSENSORS
OVERVIEW
Overview
7
The Food Standards Agency (FSA) publishes data which shows a worrying – and increasing - amount of complaints due to contamination in
food and drink. Complaints have risen year on year driven by numerous factors such as more mechanized process chain, higher consumer
awareness, and more readily available and thorough testing equipment. Physical contamination of food and drink from well-established food industry materials such as metal , plastic and glass still manage to evade
the carefully constructed safety mechanisms established to trap them
- frustrating manufacturers. Reported Incidents of contamination cause
recalls of a product, costing money and severely harm food companies
reputation - devastating to an industry who rely on consumer confidence. This problem is complicated given the varied and ever-increasing variety of materials, which are able to find their way into the food
production chain. The industry needs to be aware of what innovative sensing technologies are being developed not only in the food sector but in other sectors
also.
There are however inhibiting factors to innovation in this sector; food
industry representatives are often looking for better versions of what already exists. Engagement events are key to exposing the up and coming technologies to food industry representatives to technology areas
outside of their own areas of expertise and sector.
Although a huge industry, the food industry can be very conservative in
the adoption of new technologies and it can require much higher rates
of return on capital investment than can be delivered, therefore the food
industry seeks low- cost solutions that can justify the effort. The idea
that product recalls can be reduced or prevented by better training,
procedures etc. is a far more appealing alternative to large R&D investments.
There is however, a plethora of new technologies whose sensitivity,
specificity, cost and overall performance are beginning to align with the
needs of the food industry. Optical methods can provide real-time imaging across many wavelengths to not only detect, buy characterise
food properties as it passes through a factory. Techniques that can penetrate objects and visualise inside packages with abilities beyond what
is achievable with X-rays only are being developed for Earth observation
and military purposes which could find an unexpected application.
Valuable insight to this report was provided by interaction with food
companies through an online questionnaire, direct discussions and an
interactive workshop help on the 25th February 2014 in London which
bought together food industry experts, membership organisations and
technologists in technologies identified as potentially useful by the
Knowledge Transfer Network prior to the workshop.
The Knowledge Transfer Network: Food Sensing Report
UK SENSING TECHNOLOGIES FOR CONTAMINATION IN FOOD
introduction
Food and drink contamination
Foreign body contamination in food is one of the major sources of complaints against food manufacturers [1]. ‘Incidents’ are hugely damaging
for manufacturers as they can lead to injury, loss of brand loyalty and
large recall expenses.
Many public incidents such as glass contamination, E-coli, horsemeat
in products labelled beef have shaken trust in the industry and made
the public aware of how vulnerable parts of the food chain are to both
intentional and non-intentional adulteration.
Figure 1 shows the number of ‘incidents’ in food from 2000 in the UK,
the increase should cause alarm for all involved (Refs. 2,3,4).
The trend of increase was stalled slightly from 2006 – 2009, the subsequent increase could be due to a few factors;
Since 2009 the number of pesticide residue ingredients has increased
substantially. In 2011 and 2012, this was due partly to increased testing
of okra at border inspection posts
1714
1505
1604
1344
1298
1312
1208
966
743
530
789
476
421
2000
2001
2002
2003
2004
2005
2006
2007
2008
2009
2010
2011
2012
8
Figure 1. Number of food incidents, 2006 - 2012 adapted from Ref. 3
1. Edwards, M. (2004) Detecting foreign bodies in food, Cambridge: Woodhead Publishing Limited.
2. http://food.gov.uk/multimedia/pdfs/incidentsar.pdf Food Standards Agency (2007)
3. http://food.gov.uk/multimedia/pdfs/incidents-report-2012.pdf Food Standards Agency (2013)
4. It is important to appreciate that these figures are and are expected to be largely underestimated, by as much as a
factor of 200 suggested by some at the Workshop. This misrepresentation could be die to a variety of reasons:
• The severity of some of the incidences will bias figures towards those, for example, people will be more likely to
report a piece of glass than a fish bone.
• Once a problem is identified, mass withdrawals can hide the extent of the actual problem
• Failure to report to the FSA
Despite these obvious failings of the acquired data, the data is expected to be representative of industries problems.
INTRODUCTION
9
Incidents involving strains of salmonella has averaged out at 45 a year
during 2006 – 2009. In 2010 they rose steeply to 118 and fell only to 98
in 2012. Our investigations suggest that this increase was mostly the
result of paan leaves imported from Bangladesh (Ref. 3)
The food and drink incidents are broken down into incident type in Figure 2 for years 2006 and 2012.
Allergens
Animal feed (on market)
Biocides
Counterfeit product
Environmental contamination
Food contact materials
Illegal import / export
Irradiated ingredient
Labelling / documentation
2006
2012
Microbiological contamination
Natural chemical contamination
On-farm
Pesticides
Physical contamination
Process contamination
Radiological
TSE
Use of an unauthorised ingredient
Veterinary medicines
Water quality
50
100
150
200
250
300
350
400
Figure 2. Incident by category 2006 and 2012, Ref.3
Physical contamination is one of the key subject areas of this report
and in 2012 represented 7 % (the seventh largest category) of the total
number of complaints. In Figure 3, specifically the incidents relating to
physical contamination incidents
The “number of incidents falling into this category increased from 93 in
2011 to 107 in 2012. In particular, incidents relating to metal contamination increased from 19 incidents in 2011 to 34 in 2012”, Ref. 3
The Knowledge Transfer Network: Food Sensing Report
UK SENSING TECHNOLOGIES FOR CONTAMINATION IN FOOD
Overall the physical contamination incidents have not been improved
by a statistically significant amount over the past 6 years but for a slight
dip in 2009.
139
123
116
110
107
93
2012
2011
2010
2009
2008
2007
56
2006
10
Figure 3. Incident of ‘Physical contamination’ 2006 - 2012, adapted from Ref. 3
INTRODUCTION
11
Contaminated Products
In Figure 4, the breakdown of all incidents in 2012 is shown by the food
type they occur in. The highest categories of contamination are fruit and
vegetables, meat and meat products and nuts and seeds. The range of
detection schemes needed by the food industry is compounded by this
large number of food mediums available.
Fruit and vegetables
Meat and meat products
Nut, nut products and seeds
Prepared foods and snacks
Cereals and bakery products
Molluscs
Confectionary, honey and royal jelly
Dietic foods and food supplements
Fish and fish products
Milk and milk products
Herbs and spices
Soups, broths and sauces
Animal feeds
Non-alcoholic beverages
Poultry and poultry meat products
Crustaceans
Alcoholic beverages (other than wine)
Cocao preparations, coffee and tea
Fats and oils
Eggs and egg products
Water
Wine
Other foods
Incidents not related to a specific food
50
100
150
200
250
300
Figure 4. Incidents by food type 2012
The Knowledge Transfer Network: Food Sensing Report
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UK SENSING TECHNOLOGIES FOR CONTAMINATION IN FOOD
Types of physical contamination
The types of physical contamination present in food vary largely depending on the type of food in question, below is a short list of various
contaminant types of concern:
• Wood
• Plastic
• Metal
• Glass
• Animal origin
• Paper and cardboard
• and many more
Figure 5 and Figure 6 show the types of foreign object complaints in
2006 to 2012 (from Refs. 2 and 3). Whilst the total number of foreign objects incidents each year has fallen from 139 to 107 in this time period,
the proportion of metal incidents has risen and high-risk incidents such
as plastics and glass remain high. The reason for this may be due to a
more automated and mechanised supply chain.
Metal
Metal
19%
Pests
19%
19%
Pests
19%
2%
3%
2%
3%
8%
24%
Glass
Glass
Animal Origin
8%
24%
Plastic
Plastic
Animal
Wood
13%
Origin
12%
Rubber
13%
Wood
12%
Other
Rubber
Figure 5. Breakdown of the complaints made about foreign objects by object type
(2006)
Other
Metal
Metal
19%
32%
Pests
Pests
19%
32%
1%
3%
1%
3%
3%
21%
9%
8%
21%
9%
Plastic
Glass
3%
3%
3%
Plastic
8%
Animal
GlassOrigin
Wood
Animal Origin
Stone
Wood
Rubber
Other
Stone
Figure 6. Breakdown of the complaints made about foreign objects by object type
(2012)
Rubber
Other
The process stages in the production of a complex food are shown in Table 1 - shown also are common
points of entry for common food contamination issues. The production stages are taken from Ref. 1
Table 1. Common points of entry for contamination challenges
PRODUCTION STAGE
CONTAMINANT
PRIME PRODUCER
Insects can enter the chain at any subsequent point in this chain, perhaps
explaining why they are the second biggest complaint for food ‘incidents’,
(Figure 6). Insect and pest contamination at this stage of the supply
chain can occur as producers are under pressure to minimize pesticide
applications. The use of biological pest control may mean that damaging
insects are absent and the crop is in good visual condition, however the
predator insects may be on the produce and brought into the food supply
chain.
Glass as the fourth largest concern can enter at this stage and through
out as contaminants in the ground or later contamination by broken lights
etc. although the later contamination risk is mitigated by the prevalence of
factory safe light fittings.
The fat and gristle content of meat varies hugely from animal to animal
and is determined at this stage in the chain.
Incorrect labeling can occur at any point throughout the entire food chain,
making traceability and due diligence a key aspect of food manufacture.
HARVESTING
The harvesting process can pick up bad produce as well as physical
contaminants that are present in the environment; screening is usually
base heavily on visual inspection at this point.
Whilst plastics can enter throughout the chain, major sources are often at
the industrial processing stages, conveyer parts and tools for example.
Again, for metal, mechanised processes often increase the likelihood of
contamination at the processing stages, nuts, bolts etc.
The fat and gristle content of meat are controlled at this butchery
production stage.
Fruit and vegetables are harvested at their ripest and checked for damage
often by visual inspection after having been harvested indiscriminately.
Depending on their level of ripeness mold contamination can occur at any
stage subsequently.
TRANSPORTATION
RAW MATERIAL
PROCESSING (MILLING,
ABATTOIR)
COLLATION /
TRANSPORTATION
Bone can remain in meat and poultry products after incomplete filleting
and de-boning.
Extraneous vegetable matter (EVM) can remain during the milling process
due to its similar composition to the parent foodstuff.
FOOD MANUFACTURER
Contamination at this stage can be due to many causes, five
contamination channels at this stage could be:
Contaminated raw ingredients from the stages above.
Manufacturing machinery- rubber seals, metal swarf, nuts etc.
Packaging that is used for the ingredient or processing steps, for example
blue sacks.
Factory environment – bristles from cleaning brushes
Operators – objects that are introduced by the operators of the machinery,
hair, plasters, jewelry etc
FOOD PROCESSING &
ASSEMBLY
COLLATION, TERTIARY
PACKAGING, STORAGE
DISTRIBUTION
RETAILER RDC OR
WHOLESALER / CATERER /
STORAGE
RETAIL DISPLAY
Contaminants beyond this stage are now out of the manufacturers ability
to monitor.
CONSUMER PURCHASE &
TRANSPORTATION
The consumer assesses ripeness in fresh fruit and vegetables at this
stage.
HOME STORAGE
FOOD PREPARATION
PRESENTATION AND
CONSUMPTION
INTRODUCTION
15
HACCP
Obviously, for foreign object contamination, prevention is better than
cure and systems such as the Hazard Analysis and Critical Control
Point (HACCP) exist which set out procedures for maintaining safe to
eat food.
Hazard Analysis and Critical Control Point (HACCP) is a system that
helps food business operators look at how they handle food and introduces procedures to make sure the food produced is safe to eat. Ref.
5. As part of routine inspections, the enforcement officer will check that
the business has an appropriate HACCP-based food safety management system in place.
However, when these preventative steps fail, procedures and tests must
be in place to detect these objects, ideally identify them and ideally locate the source of the contamination.
Workshop delegates have additionally provided thought on the usefulness of sensors to not only directly detect contamination events, but
also in the behavior i.e. the breaches of HACCP which can inevitably
lead to incidences.
Recent High Profile Incidents
Table 2. Recent high profile incidents 6,7,8,9,10,11,12,13,14
INCIDENT
REF
Cigarette in Mushrooms
2014
[6]
Wasp in Chocolate
2014
[7]
Toenail in Pasta Sauce
2012
[8]
Cocaine in Soft Drink
2013
[9]
Horsemeat scandal
2013
[10]
Caterpillar in Sweetcorn
2014
[11]
Peanut in Stuffing
2014
[12]
Metal in Pudding
2014
[13]
Allegens in Hot Dogs
2014
[14]
5. http://www.food.gov.uk/business-industry/caterers/haccp/
6. http://www.dailymail.co.uk/news/article-2549331/Father-buys-pack-mushrooms-Co-op-store-finds-cigarettehidden-inside-given-just-92p-refund.html
7. http://uk.news.yahoo.com/wasp-found-inside-cadbury-dairy-milk-jake-keating-142659377.html#nHMfprI
8. http://uk.news.yahoo.com/aldi-customer-tracy-arnold-from-wisbech-shocked-after-finding-nail-in-pasta-sauce.
html#mFVJ3Ri
9. http://www.food.gov.uk/news-updates/news/2013/dec/caribbean-soft-drink#.UvUan17t0_V
10. http://www.telegraph.co.uk/foodanddrink/foodanddrinknews/9859946/Horse-meat-scandal-More-contaminatedfood-likely-to-be-found.html
11. http://www.dailymail.co.uk/news/article-2553800/Mother-finds-INCH-long-caterpillar-inside-tin-sweetcornbought-Aldi.html
12. http://www.food.gov.uk/news-updates/allergy-news/2014/feb/sainsburys-stuffing#.U1pwXl6ppuY
13. http://www.food.gov.uk/news-updates/recalls-news/2014/feb/metal#.U1pwql6ppuY
14. http://www.bbc.co.uk/news/business-27100284
The Knowledge Transfer Network: Food Sensing Report
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UK SENSING TECHNOLOGIES FOR CONTAMINATION IN FOOD
Report
objectives
This document aims to cover current detection systems used for a number of food and drink related complaints with input from food manufacturers current technologies will be assessed for their strengths and
weaknesses. Through communication with manufacturers, technologist
and consultancies future technologies are also highlighted.
The UKTI have identified key challenge areas to be met in the field of
contaminant sensing in food production. During the consultation period
further challenges (in purple) have been identified and added in addition to the initial 10. This report has been compiled by the Knowledge
Transfer Network through communication with food manufacturers,
sensor technologists and consultants and aims to detail the UK capabilities in contaminant sensing in food.
Primary Objective
The eventual aim will be to provide to the UKTI a report that can showcase the UK strengths in food sensing in its current state and also
the capacity for the UK technology base to innovate the market and
respond to the requirements of the food industry.
Secondary Objective
Creation of publishable capabilities database highlighting UK companies working in food sensing technologies as well as UK academic research groups working in relevant disciplines
METHODOLOGY
Challenges
17
1. The detection of glass fragments in liquid products filled into glass
bottles
2. The detection of glass fragments in particulate food products such
as nuts or breakfast cereals 3. The detection of plastic in any sort of food product, wet or dry,
particulate or homogenous
4. The detection and sensing of fat, gristle, cartilage etc. in meat,
prepared meat and poultry products
5. The detection of bone in meat and poultry products and bone in fish
6. The detection insects in fruits and vegetables
7. The quantification of ripeness in fruits
8. The detection of damage and of mould in fruits and vegetables
9. The identification of the wrong product in a package (e.g. fish pie in
a meat pie packet)
10. The detection of “natural plant materials which should not be
there”, for example stalks in dried fruits, shell fragments in nut
products, dense or wet lumps in breakfast cereals 11. The detection of hair and fibre in any sort of food product
12. The detection of metal in any sort of food product
The Knowledge Transfer Network: Food Sensing Report
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UK SENSING TECHNOLOGIES FOR CONTAMINATION IN FOOD
Methodology
Resources for this report have been gathered through a combination
of desk research, Internet searching, communication with food industry manufacturers (through the Biosciences community), developers of
food sensing technologies and relevant consultants. A full list of organisations assisting in the study are gratefully acknowledged and can be
found in Annex 1: Inputs to this study
The first stage of the project has been to identify the key challenges
in food sensing, 10 were initially suggested by the UKTI - further challenges were identified during the consultation procedure.
The next stage has involved communication with food manufacturers
to see how currently these challenges are being met. Potentially useful technologies were highlighted in these discussions and companies
working in these areas were contacted for their input.
The final stage of consultation was through the running of an interactive
workshop where food industry experts, technologists and membership
organisations were invited to attend to discuss a draft report prepared
by the Knowledge Transfer Network
This data from the food manufacturers is shown on pages 17 – 46. The
methods used are displayed graphically - key comments made were
also extracted.
•
Provide a comprehensive study of the challenges faced by food
manufacturers
•
Identify key technology areas to meet the challenges
•
Promote opportunities for sensor companies in the food sector
•
Provide a map of UK capability in the contaminant sensing sector
•
Provide a networking opportunity for interested parties
The final report will be made available on the Knowledge Transfer Network website – freely downloadable for all interested parties, who could
include:
•
Sensor companies with an interest in non-destructive evaluation in
food processing
•
Food processing companies who wish to investigate options for
detection
•
People working in linked sectors with an interest in foreign body
detection
CURRENT APPROACHES
Current
Detection
Approaches
19
There are a few important qualifiers that a detection scheme should be
compared against ultimately determining whether it is appropriate for its
purpose. The respondents to the questionnaire were asked to consider
the following qualifiers.
The cost of a device is always a concern for manufacturers. High installation costs can sometimes be countered by low maintenance costs.
However, it should be noted that the price of safety infractions can be
very high not only in fines, but in recalls and loss of consumer credibility.
The ease of use covers how complicated the device is to operate and
how easy the results are to interpret. This is linked strongly with cost – if
a team of technicians are required to operate, monitor and maintain the
device then it may become economically non-viable.
The sensitivity of the device will determine how small a foreign contaminant can be discovered and how accurately a characteristic can be
measured. This is clearly an important feature as small shards of glass
for example can be just as dangerous and large chunks.
The speed of a measurement will determine the throughput of food to
be checked. Slow time-consuming measurements may end up revealing more accurate results but the time lost may not be worth it, and vice
versa a very quick machine that has very high throughput but misses
every other object will not be wanted. Speed also encompasses how
quickly results take to be analysed; can they be done on sight? Do they
need a lab?
The specificity of the device will determine whether it is capable of
identifying specific information about a contaminant. For example, can
it tell the user exactly what type of plastic is in my food? Information
such as this is invaluable when locating the source of a contamination
– as this can save manufacturers vast amounts of money in lawsuits,
shorter shut down periods etc.
What is the size of the detector? The platform for the sensor device
can vary from a large factory based scanner, a hand held device, mobile phone integrated sensor, on product sensor (a sticker for example).
There are obviously advantages for more discreet sensors in food production locations where space is at a premium.
Additional extras: are there unique properties to the device that aren’t
covered above, can it measure more than one contaminant? Penetration depth? Can it be retrofitted to existing lines? – a large barrier to
entry in this market, etc. The following pages provide some detail on the technologies currently
being used, along with their advantages and disadvantages. They
are divided into off-line techniques, on-line techniques and potential
techniques for innovation that aren’t yet in wide scale use.
The Knowledge Transfer Network: Food Sensing Report
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UK SENSING TECHNOLOGIES FOR CONTAMINATION IN FOOD
Current
approaches
Electromagnetic
spectrum
The approaches identified are separated into on-line and off-line techniques, they are assessed based on their technological capabilities,
their applicability to food contaminant sensing both for liquids in a pipe
and particulate food on a conveyor, pros and cons and (if applicable)
the UK capabilities
For off-line techniques, comment is not made on their applicability to
pipe and conveyor - they are included for completeness.
As many of the techniques listed below are based on either the absorption of scattering of parts of the electromagnetic spectrum, it is perhaps
useful to remind the reader where the different regimes lie.
Figure 7. The electromagnetic spectrum, taken from Ref. [15]
15. http://www.physik.uni-kl.de/en/beigang/forschungsprojekte/
ON-LINE TECHNIQUES
On-line
Techniques
21
X-ray imaging
X-ray imaging uses the absorption / transmission of X-rays to
produce images. These images relate to the cross-sectional density
of the material being probed. Both two and three - dimensional
images can be constructed using tomographic imaging. Whilst some
manufacturers may express concern over the quality of food after
being subjected to X-rays – the World Health Organisation (WHO) have
confirmed that food radiation levels up to 10,000 Sv do not affect food
safety or nutritional value - doses used in inspection technologies are
significantly lower than that.
Due to the ability for X-rays to differentiate materials of differing densities, X-ray imaging can be used to identify contaminants such as metal,
stone, glass, dense plastics and calcified bone. These machines are
commonplace in food inspection lines due to their low maintenance
needs and the relatively easy interpretation of results. The future for Xray imaging could include the incorporation of material discrimination
and fat analysis into one system.
The sensitivity and range of application of the X-ray inspection methods could be increased by the addition of energy sensitivity, allowing
unique identification between thickness and material changes, and thus
increasing the contrast of low absorption materials such as plastics and
organics.
The benefits of using energy X-ray sensitive detectors to detect impurities is well understood, but it has probably not been adopted for in-line
food inspection as the existing technology using CdTe or Ge is prohibitively slow and too expensive.
Applicability to liquid in pipes
Due to the low absorption cross-section of materials available for industrial food processing pipework – the application of X-ray imaging
systems through pipes is not unusual. There exist on the market pipeline X-ray systems for the continuous inspection of pumped products
– suitable for fluids, semi-solid products such as sauces and fruit preparations.
Applicability to particulate food on a conveyor
X-ray systems are well suited for quickly identifying abnormalities in line
product products. The image processing and rejection decisions can
be made automatically with pattern recognition software of by human
monitoring in a way similar to airport package monitoring.
The Knowledge Transfer Network: Food Sensing Report
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UK SENSING TECHNOLOGIES FOR CONTAMINATION IN FOOD
Table 3. X-ray imaging usefulness in the food sector [16]
PROS AND USES
CONS AND LIMITATIONS
Can penetrate deep within the
sample travelling through packaging.
The X-ray beams are ionising – this causes little to no
damage to the food under inspection but can cause health
problems for operators accidently exposed to the beam.
It is a non-destructive technique,
non-contact technique
Capabilities:
• Metal
• Glass
• Stones
• Calcified bones
• PVC plastic
• Teflon
• Ceramics or concrete
• Flavour / sugar clumps
• Missing product
Applicable for ready meals, prepared foods, meat, bakery products,
cereals, dairy foods, confectionary,
vegetables, fruit, cosmetics.
Limitations:
• Low-density plastics
• Thin glass
• Low-density stones
• Insects
• Wood
• Hair
• Cardboard
• Paper
• Non-calcified bones
Linked sectors
Healthcare: Perhaps the most common use of X-ray imaging is in medical healthcare where 2D and 3D images are constructed of patient interiors. Hard X-rays are also used in the medical treatment of cancer.
Material Science: Hard X-rays are often used in material science for
non-destructive testing of crystallographic information etc.
Astronomy: There are various sources of X-rays in the Universe which
are studied by scientists, detectors for hard radiation are used in this
sector.
Security: A very common use of X-ray imaging is in security applications to see through packaging and luggage for non-destructive security testing.
16. http://www.loma.com/lo_xray_guide.shtml
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X-ray spectroscopy
X-ray spectroscopy uses the scattering or absorption of X-rays to provide qualitative information on the electronic structure of the sample.
Absorption and scattering of X-rays gives a material dependent spectrum allowing for identification and composition of various materials.
X-ray spectroscopy can be found in off-line and on-line solutions to
food quality testing. Unlike X-ray imaging however the technique often requires more complicated detection systems than X-ray imaging
by use of X-ray dispersive optics or solid-state X-ray energy analyzers.
Some examples from Ref. 23 of X-ray spectroscopy are EDAX analysis
to determine phosphorous content of potato starch and also as trace
element detection for specific contaminant detection. A further example
of ham identification is detailed in Ref. [17] – high flux synchrotron radiation identified signatures in cured ham unique to the curing process
helping to establish a test against ham fraud.
Applicability to liquid in pipes
For spectroscopy techniques in the photo absorption regime, X-rays
are often tuned to core energy levels of electronic structures – this often
puts the energy of the X-rays at the low energy end that severely limits
the penetration depth. Spectroscopy through pipes and semi solid liquids would be difficult to achieve [18].
Applicability to particulate food on a conveyor
An easier application for X-ray spectroscopy measurements would be
in particulate solids on a conveyer, X-rays would only penetrate minimally into the surface and collection and analytical time may however
severely limit throughput.
17. http://www.esrf.eu/Apache_files/Newsletter/ESRFNewsSep2010.pdf
18. There are spectroscopic techniques higher in energy, although the application of these would be fraught with
difficulty for interpretation.
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Table 4. X-ray spectroscopy usefulness in the food sector
PROS AND USES
CONS AND LIMITATIONS
Very specific method of
identification
Spectrum analysing sources
require complicated
equipment.
Can penetrate deep within
the sample, travelling through
packaging
Scans can take longer than X-ray
imaging
Capabilities:
• Metal
• Glass
• Stones
• Bones (only calcified)
• PVC plastic
• Teflon
• Ceramics or concrete
• Flavour / sugar clumps
Missing product
Energy dispersing CCDs or
solid state detectors are
expensive
Only reasonable small areas
can be examined at a time
Limitations:
• Low-density plastics
• Thin glass
• Low-density stones
• Insects
• Wood
• Hair
• Cardboard
• Paper
Applicable to ready meals,
prepared foods, meat, bakery
products, cereals, dairy foods,
confectionary, vegetables, fruit,
cosmetics.
Linked sectors
Material Science: soft X-rays are often used in material science for
non-destructive testing, electronic structure analysis, magnetic information, compositional analysis etc.
Astronomy: There are various sources of X-rays in the Universe that
are studied by scientists, detectors for hard radiation are used in this
sector.
Healthcare: In pharmaceuticals X-ray spectroscopy is routinely used
for quality control of catalyst concentration and foreign matter.
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Raman spectroscopy
Raman Spectroscopy is a method of vibrational spectroscopy long
known to the condensed matter physics world and is a technique which
provides information on rotational and vibrational modes in materials –
as such provides ‘fingerprint’ information of substances that are unique
to that substance.
In Raman spectroscopy, a sample is illuminated by a monochromatic light source, this light is used to promote electrons from vibrational
states into higher level virtual states, as the electron falls back into its
ground state, light is radiated which is specific to that vibrational state
(Figure 8). The scattered light is then measured on a detector. Summing
over all the present vibrational states results in a spectrum that is unique
to a substance.
In food technologies, Raman spectroscopy may be used as a tool for
quality control, for compositional identification (fatty acid composition,
fish and meat muscle quality) or for the detection of adulteration, as well
as for basic research in the elucidation of structural or conformational
changes that occur during processing of foods (changes in proteins,
water and lipids that occur during deterioration), Refs [19 and 20].
Applicability to liquid in pipes
Obtaining Raman spectra from liquids or semi-solid liquids is possible
wherever there are molecular bonds – fast moving, inhomogeneous
samples however will prove difficult to obtain a good Raman spectrum
for.
Applicability to particulate food on a conveyor
The speed of data collection can again cause difficulties for on-line detection, but it is classed here as an online technique due to its abilities
as a remote detection scheme. Another issue may be the small sample
volumes obtainable – as to the best of the authors knowledge, widefield Raman imaging is not a well established technique [21].
19. Raman Spectroscopy a promising technique for quality assessment of meat and fish: A review, Food Chemistry,
107, 1642 (2008)
20. The applications of Raman spectroscopy in food science, Trends in Food Science & Technology, 11, 361 (1996)
21. There are methods, however, available for building Raman images, but these often rely on point by point scanning
and can be very time consuming, Raman Imaging: Techniques and Applications. Arnaud Zoubir, Springer Series
(2012)
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Table 5. Raman usefulness in the food industry
PROS AND USES
CONS AND LIMITATIONS
Non-contact
No commercial solutions for
food
Non-destructive
Can be enhanced greatly using
nanostructures to provide
surface-enhanced Raman
scattering which can be capable
of single molecule detection levels
Fluorescence can be a
problem for detection.
Hard to develop wide field
solutions
Very weak response to water
Linked sectors
Healthcare: Raman gas analysers are used in medicine for real-time
monitoring of anesthetic and respiratory gas mixtures during surgery.
Pharmaceuticals: identification of pharmaceutical constituents can be
made using Raman.
Security: Raman scanners have found a large market in airport security
due to their fingerprinting abilities [22].
Figure 8. Example of Raman spectroscopy of native starches from Ref. [23]
22. http://physicsworld.com/cws/article/news/2012/feb/07/raman-technique-peers-into-cabin-baggage
23. Characterization of Irradiated Starches by Using FT-Raman and FTIT Spectroscopy, Journal of Agricultural and
Food Chemistry, 50, 3912 (2002)
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Visual Inspection
Visual monitoring of foodstuffs uses humans as resources to watch the
food move past, any thing that doesn’t conform to the standard is taken
from the production line. The definition of non-conformity is vital to be
established from the outset. Many production facilities set out the criteria for non-conformity see Refs [24] for examples.
Applicability to liquid in pipes
Only very obvious problems can be identified using visual inspection
of food and liquids in pipes, more often that not - visual inspection is
enhanced by providing the use of X-ray technology for the inspector to
see through obstructing pipes.
Applicability to particulate food on a conveyor
Visual identification is easier for discrete items on a conveyer than in a
pipe, again is assisted by the use of non-standard imaging techniques
to assess uniformity. Other sensory inspection could help here, such as
smell or touch.
Table 6, Visual inspection usefulness to the food sector
PROS AND USES
CONS AND LIMITATIONS
Non-destructive technique
Very resource intensive
Can be used as a monitor for
many defects in one
Highly variable outputs
24. Guidelines Procedures for the Visual Inspection of Lots of Canned Foods for Unacceptable Defects, CAC/GL 17
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Infrared techniques
Near Infrared (NIR) spectroscopy uses the different absorption conditions of different compounds to analyse the constituent elements of a
sample. The NIR region extends – roughly – from 800 nm to 2500 nm
and is thus very well suited for the detection of organic compounds. The
technique uses transition probabilities of photons to map the states in
a material.
In the food industry NIR spectroscopy has been used for many years
to determine the food quality in an accurate, non-destructive and rapid
way. Due to its sensitivity to organic content (water, sugar, acids etc.) - It
can be used to determine moisture, fat and protein content and other
components that impact on product quality and safety. some firms are
currently marketing NIR based sorting and grading systems for use with
citrus, pome and stone fruits As well as being able to detect the presence of organic content the technique can be used to fingerprint what
the content is (useful for pathogens, allergens etc) and with plastics being composed of organic chains, plastic contaminants can not only be
located, but also identified.
MIR is very rich in the information it provides for organic materials in
terms of the fine structure in the spectrum.
Applicability to liquid in pipes
There are product solutions of pipe-mounted NIR liquid process cells
for monitoring. NIR spectroscopy, however, suffers from strong absorption in water, as such applicability to liquids in pipes may be limited and
the penetration depth of the NIR beam would severely limit the diameter
of the process pipe.
Applicability to particulate food on a conveyor
Particulate food on a conveyer is well suited for NIR inspection and
there are products that analyse the NIR spectrum of food and beverages. Quicker measurements are available by sing FT-IR spectroscopy
(see one of the following next sub-section).
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Table 7. NIR usefulness in the food industry
PROS AND USES
CONS AND LIMITATIONS
Easier maintenance than X-ray
machine
Short penetrating length
Uses non-ionising radiation, i.e.
safer than X-rays
Non destructive
Real-time measurements
Little or no sample preparation
Due to its sensitivity to moisture,
proteins, fats and sugars it
is ideally suited for the dairy
industry
InGaAs or PbS detectors less
sensitive then visible CCDs.
The strong absorption in
water has historically limited
the use for assessment of
fresh produce
Calibration limitations
Good applicability to fruit
Good applicability to identifying
presence of organic content
Linked sectors
Astronomy: spectral information can tell astronomers about star types
and stellar formation and processes.
Healthcare: used to measure oxygen content of blood, and also can be
used on the skull to provide information of blood flow related to neural
activity as a partial replacement for fMRI (functional MRI)
Materials: can be used to measure film thicknesses for optical coatings.
The technique is closely linked with hyperspectral imaging (HSI) described in the following section, due to its proximity in the EM spectrum, HSI is where optical measurements are combined with imaging to
provide images containing not only spatial information but wavelength
information. The difference in these technologies is often in the detections scheme-in NIR spectroscopic information is often obtained using
dispersive elements whereas in HSI, the detector is constructed as to
observe many wavelengths simultaneously.
FT – IR spectroscopy
FT-IR (Fourier transform infrared spectroscopy) is considered a more
sensitive and robust technique over dispersive NIR techniques described above by its lack of diffraction grating to separate out frequencies – instead interferograms are collected by a interferometer-like setup
which represent the Fourier transform of the absorption spectrum.
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FT-IR has the following advantages over dispersive and filter methods
of IR or NIR methods:
Table 8. Advantages of FT-IR over dispersive IR, from Ref [25]
PROS AND USES
It is non-destructive
Solids, liquids and gases can be analyzed
It is possible to easily identify and distinguish between many
organic compounds and inorganic compounds
Precise measurement method that requires no external calibration
FTIR measurements can be made within seconds
Optimal sensitivity – detectors are more sensitive and the optical
throughput is higher. FTIR can identify small concentrations of
contaminants.
Mechanical simplicity – The mirror in the interferometer is the only
moving part in the FTIR instrument, therefore making mechanical
breakdown minimal.
Simultaneous analysis of multiple gaseous compounds
25. http://www.aircomp.com/blog/advantages-of-ftir-over-dispersive-methods-of-infrared-spectral-analysis/
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Hyperspectral imaging
The hyperspectral imaging (HSI) method combines digital imaging with
spectroscopy for give detailed information across multiple ranges of the
EM spectrum. Unlike single source detection systems, hyperspectral
imagers collect data from across the electromagnetic spectrum. Hyperspectral imaging can be perceived as an extension of multispectral
imaging (MSI); while multispectral imagers look at light from up to 10
wavebands, hyperspectral imagers are capable of obtaining information in a more continuous fashion, over 100 wavebands. Data are therefore not stored as two-dimensional images but instead as cubes, where
the third dimension spans the wavelength range of the detector. These
cubes are unique for every produce and serves as a reference for the
sorting procedure.
The use in food can be in using the ‘fingerprinting’ ability to determine
what the constituents of the passing food are and whether it should be
there. Indeed there exist some commercial solutions already.
Applicability to liquid in pipes
Many of the disadvantages of liquid in pipe sensing for NIR are shared
with HSI.
Applicability to particulate food on a conveyor
HSI lends itself well to conveyor inspection lines - the advantage of
simultaneous acquisition across many wavelengths allows quick gathering of vast amounts on information, see for example chicken carcass
inspection Ref. [26].
PROS AND USES
CONS AND LIMITATIONS
Non-contact, non-destructive
Few commercial solutions
Due to the multi-wavelength
approach vast amounts of data
are recorded simultaneously
Expensive detection systems
for HSI
Large area detection
Applications in differentiating
organic components
Limited penetration length
Large storage capabilities
required
Extraneous vegetable matter
Stones and shells
Meat and poultry contamination
26. Hyperspectral waveband selection for contaminant detection on poultry carcass, Opt. Eng. 47(8), 087202 (2007)
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Linked sectors
Due to its fingerprinting and identification capabilities hyperspectral imaging can find uses in various linked industries.
Astronomy: mapping the physical properties of cosmic hot gas.
Security: in forensics hyperspectral imaging can be used for detection
of forged documents and fingerprints at crime scenes.
Environmental monitoring: Hyperspectral imaging can be used to
monitor vegetation and has been equipped to UAVs to detect large images.
Medicine: extent of burns and bruises below the skin of the human
body, skin imaging for the diagnosis of skin cancers. In pharmacology
it can be used discern the makeup of drugs that look identical to the
naked eye and conventional imagers.
Figure 10. The image on the left shows raisins with impurities in between (paper,
plastic). The blue and green arrows point two spectral positions of raisins. In the
graph on the right it can be seen that points with similar color also have similar
spectra behind. The red arrow points a different color. Taken from Ref. [27].
27. http://www.perception-park.com/what-is-chemical-color-imaging.html
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Optical sorting
Optical sorting methods use advanced image recognition equipment
to automatically identify shapes, size, color and patterns of items that
do not fit set parameters, current systems. The spectral information /
images could be from any other optical sensor techniques shown above
– more often than not however, they are based on monochromatic or
tri-chromatic cameras.
Optical sorters are widespread in the food industry due to its in-line,
non-destructive and low human resource use. Compared to manual
sorting, which can be is subjective and inconsistent, the non-reliance on
human resources helps improve quality of products, maximize throughput, increase yields and reduces labour costs. From Ref 28, in meat, it
has been used to characterize muscle colour, marbling, maturity and
muscle texture. In other applications sorting technologies have been
used in agricultural products such as fruits, vegetables or grain.
In general, and optical sorting system is composed of four major components; the feed system, the optical system, image-processing system and the separation system. The optical system can be integrated
with advanced technologies such as hyperspectral sources which as a
great deal of functionality to the system.
Applicability to liquid in pipes
The applicability and usefulness in pipes is essentially the same as that
for inspection by humans, except it takes out the uncertainty and random errors associated with human monitoring.
Applicability to particulate food on a conveyor
See above
28. Irudayaraj, J and Reh, C. (2008) Nondestructive testing of food quality, Blackwell Publishing Ltd.
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Table 9. Optical sorting usefulness in the food industry [29]
PROS AND USES
CONS AND LIMITATIONS
These systems can be very
specific
Due to the integration of
robotics, can be reasonably
expensive.
Automation means that human
resource costs are low
100 %, on-line inspection
Applicable to:
Seeds
Can give information of the
wrong shape and size, but
not applicable to all types of
defects
Limited to transparent /
surface incidents
Coffee
Fruit
Grain
Nuts
Linked sectors
Pharmaceutical: in this sector optical sorting is used for optimizing the
end products of pharmaceutical products ensuring quality, efficient and
reliability.
Industrial: can be used for automated machine building tasks, waste
recycling, tobacco processing.
A comparison of RGB imaging, NIR spectroscopy, multispectral imaging
and HSI are shown below for a comparison (adapted from Ref. [30]).
Table 10. Comparison of RGB, NIR, MSI and HSI techniques
ATTRIBUTE
Spatial information
RGB
Sensitivity to minor components
MSI
HSI
P
P
P
Limited
P
P
Limited
P
P
Spectral information
Multi-constituent information
NIR
Limited
P
29. http://www.buhlergroup.com/global/en/process-technologies/optical-sorting.htm#.Uut1lHm4ml
30. Potential application of hyperspectral imaging for quality control in dairy foods, Gowen et al, Image Analysis for
Agricultural Products and Processes, 65, (2011)
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Terahertz imaging
Terahertz (THz) radiation lies in-between microwave and the far infrared on the EM spectrum generally with a wavelength range of between
100 µm and 1 mm corresponding to frequencies of 0.3 to 3 THz. Unlike
microwave radiation it can penetrate a wide variety of non-conducting
materials. Non-destructive evaluation, the energy of the THz band is 1
– 10 meV. T-rays are inherently sensitive to water; they are very suitable
for moisture detection. Transparent to opaque materials such as plastic, fabric, ceramic and paper so the technology has the ability to see
through some packaging materials.
THz has applications in food technology due to its strong interaction
with water. Moisture content can be used to infer different properties of
a foodstuff – fat content, ripeness etc. Its ability to see through plastics
and card also make it perfect for NDE of packaged food
Applicability to liquid in pipes
High water content materials are almost completely opaque to THz radiation, this in conjunction with possible metal piping means that THz
imaging and spectroscopy has very limited uses to liquid phase food.
Applicability to particulate food on a conveyor
For less water intense materials, the opaqueness of water to THz can
provide a wealth on information for moisture detection. Its ability to see
through paper, plastic can check for missing items on a conveyor.
Table 11. THz usefulness in the food industry
PROS AND USES
CONS AND LIMITATIONS
On-line, non-destructive
technique
Metal and polar liquids (such
as water) completely opaque
to THz radiation
Many more materials are
transparent to THz radiation (as
compared with IR)
Non-ionising.
THz radiation cannot
penetrate metal
Expensive sources and
detectors are major
obstacles for commercial
devices
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Linked sectors
Due to the ability of THz radiation to penetrate common packaging and
clothing materials there is interest from sectors such as:
Healthcare: unlike X-rays THz radiation is non-ionising and therefore a
safer alternative for medical applications. It also has the ability to distinguish areas of different density and water content.
Security: the non-ionising properties of THz radiation also makes it an
attractive method for concealed weapon detection through clothing, the
additional method of THz spectroscopy allow the unique fingerprints of
substances to be exploited and identify concealed substances.
Manufacturing: uses in manufacturing, quality control and process
monitoring due to the transparent properties of cardboard and plastic,
the inspection inside packaged goods can take place.
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Microwave detection
Microwaves are no stranger to the food industry – the ease at which
microwaves are generated coupled with the strong absorption by water
make them ideal for microwave heating devices. Detection systems that
operate in the microwave part of the spectrum are far lower power - Ref.
[1].
Microwave imaging is uncommon as the large wavelength for small
objects result in diffraction effects and a severely limited image when
compared with X-ray imaging for example. Microwave detection systems instead rely on measuring the transmitted microwave field passing
through a product and the local variation in dielectric properties between
foreign objects and the product. Dielectric discontinuities are seen as
absorption change of phase. Similar to THz radiation, though possessing higher penetration depths microwave radiation has a wavelength
range of between around 1 cm and 30 cm corresponding to a frequency
range of 200 MHz to 300 GHz.
Active microwave technology for this area is much closer to commercialization than THz equipment, with sources and detection methods
well established from areas such as telecommunication. Unlike microwave ovens, the radiation used in low power and more similar to an Xray imaging set-up. Additionally due to its response to water, microwave
wavelengths have been proposed for use in measuring water content
for ripeness determination, see Ref. [62].
Applicability to liquid in pipes
A Swedish company – Food Radar – has commercialized a product using microwave radiation; the transmission of the microwave radiation
is dependent on the permittivity of the transmission medium. Foreign
objects change a materials permittivity and the detected radiation can
thus be monitored for contamination – applicable to liquids and emulsions. It is claimed that glass (10 mg pieces), metal filings (5 mg), plastics, stones, wood and other organic materials can be detected with
microwave techniques,
Applicability to particulate food on a conveyor
Microwave sensing can still be applied to food on a conveyor provided
they are not in metal packaging – unpackaged, wood, plastic etc. But
the technique is best suited for homogenous, piped foods if possible.
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Table 12. Microwave radiation usefulness in the food industry
PROS AND USES
CONS AND LIMITATIONS
Non-contact, non-destructive
No UK commercial solutions
Very wide range of contaminant
materials detectable by their
microwave impedance.
Not ideal for imaging
No limits on speed of flow through
the food-processing system.
Good for metal, glass, stone and
voids. Unique in its ability to
measure wood, stones, plastics,
shells, rubber, seeds, paper
Linked sectors
Astronomy: the microwave background in the Universe provides evidence of the forming of the universe and various other extra-terrestrial
microwave sources.
Communication: Many communication protocols operate in the microwave range. An advantage of microwaves over radio waves is that the
microwaves have a higher frequency and therefore can encode more
information.
Healthcare: There are examples of microwave imaging being used for
the detection of breast cancer
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Ultrasound
Ultrasound uses the transmission and reception of high frequency, low
power ultrasound (pressure waves) to locate foreign bodies by being
able to differentiate discontinuities in acoustic impedance by analysis of
original and reflected waves. In doing so, can determine composition,
structure and physical state.
Ultrasound has been used in food technology for many years [31]. It can
be divided into two areas; high frequency, low power and low frequency,
high power, the low energy is used for quality assurance and process
control and high power ultrasound is an emerging technology area for
modification of food (not the focus of this report). For process monitoring, recent publications detail the use of ultrasound on canned foods,
Refs [32,33]
Applicability to liquid in pipes
Impedance matching is far easier for liquids in pipes than discrete objects as better contact can be made between transducer and the object
of interest. The transducer can assume various geometries and the pipe
itself can act as the transducer as it will always be in contact with the
food material - Ref. [34]
Applicability to particulate food on a conveyor
Difficult to achieve in practice due to the requirement of contact, although there have been proof of principle demonstrations of ultrasound
applied to canned foods and cheese, Refs [35-36]. Detection is more
difficult in inhomogeneous samples.
Linked sectors
Whilst high-power ultrasound has many applications in industrial processing, low power ultrasound is generally used for non-destructive
evaluation (NDE) an has many applications:
Healthcare: 2D and 3D imaging are possible in human and animals using ultrasound and is an attractive technique due to its lack of ionizing
radiation and relatively inexpensive and portable equipment.
Industrial processes: used extensively in the aerospace industry for
evaluating cracks and detects in composites and metals. Can also be
used for materials such as wood, concrete and cement.
Security: Commonly used in underwater applications as SONAR for
range finding and object location
31. Applications of Ultrasound in Food Technology, Acta Sci. Pol., Technol. Aliment. 6(3), 89 (2007)
32. Detection of foreign bodies in canned foods using ultrasonic testing, International Food Research Journal 19(2),
453 (2012)
33. Online Detection of Contaminants in Packaged Foods with Ultrasound using Signal and Image Processing and
Soft Computing, Mittal and Basir, IEEE (2009)
34. Ultrasound in Food Processing, M. J. W. Povey, Springer Books ()
35. Detection of foreign bodies in canned foods using ultrasonic testing, International Food Research Journal, 19, 543
(2012)
36. Ultrasound detection and identification of foreign bodies in food products, Food Control, 12, 37 (2001)
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Table 13. Ultrasound usefulness in the food industry
PROS AND USES
CONS AND LIMITATIONS
Rapid
No commercial solutions
Non-destructive and on-line
Good contact required
between transducer and
object to reduce impedance
mismatch, difficult for online
systems.
Low power usage and safety
Ultrasound can be coupled to
liquids in pipes very well.
Well suited for, large acoustic
impedance contrasts, missing
items.
Well suited for liquids in glass
bottles
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Magnetic Separation
Magnetic separation can be used to filter out the “tramp” iron that can
find its way into a production from fields or processes. Low intensity
magnetic fields are applied to the moving sample of solid or liquid food.
The field may be applied from a permanent magnet (high field rare-earth
magnets such as SmCo5 or Nd2Fe14B) or electromagnets.
Applicability to liquid in pipes
The effectiveness of magnetic separators is reduced in damp food; the
technique however is effective in free flowing liquids
Applicability to particulate food on a conveyor
Embedded metal contaminants will remain embedded in large, dense
food objects. Instead the ideal situation for magnetic separators are
small, discrete foodstuffs like nuts, flour etc.
Table 14. Magnetic separation usefulness in the food industry
PROS AND USES
CONS AND LIMITATIONS
Non power consuming, passive
detection
Invasive and requires
maintenance
Simple to operate
Substance must be magnetic
Applicable for some metals and
can remove objects as small as a
few microns.
Large magnetic fields can be
hazardous to health
Can be used well for cereals, nuts,
flour
Not applicable to non freeflowing or damp mediums
Linked sectors
Industrial processes: such as mining iron, removing useful magnetic
components from scrap etc.
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Metal detection
In standard metal detection techniques, an RF signal transmitted by
the detector is compared with the one received. Non-metallic material
passing through the RF field does not distort the RF field. Metal passing
through the signal fields however will distort the normal pattern of the
electrical fields. Distortion limits can be set to detect very small metal
inclusions.
Applicability to liquid in pipes
Solutions exist for pipeline metal detectors as RF signals can be used
through pipes and metal work. The contamination being present in a
liquid phase does not complicate the detection significantly.
Applicability to particulate food on a conveyor
As RF signals can penetrate deeply through a medium – large, dense
objects can be screened by metal detection techniques.
Table 15. Metal detection usefulness in the food sector
PROS AND USES
CONS AND LIMITATIONS
High level of sensitivity
Only detects conductive
materials
Non-destructive
Metals need not be ferrous
Biased towards magnetic
materials
Many food products are
conductive
Linked sectors
Archeology: both as a hobby and industrially metal detectors are used
to locate metal objects of interest underground.
Military: a very common use of industrial metal detection is in the security sector capable of measuring very small metal objects.
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Sampling
Sampling techniques involve sampling parts of the production line as
to get a statistical idea of the quality of the entire production line. The
sampled section of the line can then be subjected to further off-line
tests to check for conformity.
Applicability to liquid in pipes
Sampling can be performed for both liquids and particulate objects.
Careful consideration must be given to the sampling frequency as under
sampling can result in poor coverage and oversampling can be time
inefficient and expensive.
Applicability to particulate food on a conveyor
See above
Table 16. Sieving and sampling usefulness to the food sector
PROS AND USES
CONS AND LIMITATIONS
Can perform any measurement on
the sample once the foodstuff has
been samplede
Statistical approaches can
easily overlook contaminants
Linked sectors
Visual inspection, sieving and sampling are used for all industries as at
very least a check that automated processes are performing correctly.
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Electrical impedance
Perhaps one the most simple measurements one can perform to locate
foreign objects is to utilize the change in impedance inherent with a
foreign object contamination event.
For an AC signal, the change in resistance, capacitance and inductance
are related to the complex impedance of the sample, which affects the
signals magnitude and phase. Changes in a materials complex impedance will result in measurable signal changes which can be used as an
indicator of contamination.
Certain physical changes in food structure and state can have an effect
on the electrical properties. As a couple of examples electrical transport
anisotropy of meat was able to determine the ageing of meat, Ref. 37.
Applicability to liquid in pipes
In Ref. [1] is shown an example of how an electric system tuned close to
resonance can act as an effective foreign body locator in piped foods. in
a steady flow the resistance should be fixed – foreign objects would affect the resistance of this flow. The sensitivity of this device comes from
its proximity to resonance – and thus its susceptibility to any change
in the resistance. Shown in Figure 11 is an example of the detection of
small non-metallic impurities by phase measurements. Foreign objects
alter the output electrode signal close to the resonant frequency of the
system resulting in a large output change (again from Ref. 1).
Applicability to particulate food on a conveyor
One current application of impedance-based system is designed to
detect damage in bottles (a key cause of glass contamination) – the
system applies a high voltage electric field to four points around the
circumference of the bottle, any damage shows itself as a change in
the impedance when compared to a reference sample and is capable of
detecting hairline cracks, Ref. [1].
Table 17. Electrical usefulness in the food industry
PROS AND USES
CONS AND LIMITATIONS
Non-destructive
No UK commercial use
Simple experimental set-up
Can detect anything that has
different impedance properties to
its surroundings, so applicable to
glass, rubber, plastic, metal etc.
37. Electrical impedance probing of the muscle food anisotropy for meat aging control, Food Control, 10, 931 (2008)
ON-LINE TECHNIQUES
45
Linked sectors
The electrical properties of materials are used across many industries
as it can give detailed information on the microscopic behavior of the
charge carriers.
Figure 11. Response of the impedance sensor to non-metallic foreign bodies taken
from Ref [1]
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Off-line /
Lab-based
Techniques
Biosensors
Biosensors are devices that detect an analyte that combines a biological component with a physiochemical detector component. In the
food industry these sensors are often associated with the detection of
pathogens and food toxins. Although may have applications where the
analyte is not a pathogen but another indicator of interest, ripeness for
example. The potential uses for these are very broad. Advances in sensor production mean that these can be made very cheaply.
Table 18. Biosciences usefulness in the food industry 38
PROS AND USES
CONS AND LIMITATIONS
Wide range of detectable
contaminants, E-coli, MRSA,
toxins representative of animal
contact, moisture, allergens
Tend to be for chemical
contamination testing
Contact method
Can be integrated into packaging
/stickers, see for example Ref.
[38]
Linked sectors
Taken from Ref [39]
Healthcare: increasing lifetimes with increasing ailments, increasing
affluence and expectation of well-being are expected over all timescales and with the large functionality of biosensors this is an important
driver.
Industrial processes: Energy costs and resource efficiency are issues
that will extend to the long-term
Environmental: Legislation and public opinion, global climate are medium and long-term drivers. Much work is being done in this area to
develop generic biosensors that can detect a range of contaminants in
water / air necessitated by EU legislation.
Security: one-off events and global conflict can initiate both shortterm needs for example (for anthrax detectors) and longer-term policy
changes.
38. http://www.ripesense.com
39. UK Sensor Company Capability and Opportunities Study, To be published 2014, ESP KTN
OFF-LINE / LAB BASED TECHNIQUES
47
Nuclear magnetic resonance
Nuclear magnetic resonance (NMR) uses RF excitations to cause nuclei
to precess in the presence of a magnetic field, the relaxation of the nuclei give great detail on the content of the sample and its environment.
Due to the historic use in the medical industry this technique is very well
suited for meat analysis. Ref [40] gives a detailed overview of where the
technique is currently being employed by the food industry – although
still limited to the academic world due to high equipment costs and
resource inefficiency.
Whilst there exist many commercial solutions, these remain expensive
and bulky due to the requirement of high fields. Earth field NMR machines do exist but fail to deliver resolutions that are required for industrial practices.
The UK academic community has ample access to NMR machines often
based in material science department at Universities such as Warwick,
St Andrews, Cambridge, Sheffield, Durham, Nottingham, Glasgow, Oxford, Birmingham, Queen Mary University of London, Imperial College
London, York, Bristol, Southampton, Liverpool, Newcastle, Sussex
Table 19. NMR usefulness in the food industry
PROS AND USES
CONS AND LIMITATIONS
Very sensitive
Can be very expensive
Ideal for meats / organic tissue
Resource heavy for powerful
magnets
Non-contatc, non-destructive
Samples must remain
stationary
Linked sectors
The technique of NMR has applications in many other sectors such as:
Material science: NMR spectroscopy can be used to study the chemical structure of a material, time domain NMR spectroscopy is used to
molecular dynamics of systems by matching the RF frequency to element of interest.
Healthcare: a very important application for NMR is that of magnetic
resonance imaging (MRI) - the 3D imaging and analysis of human and
animal tissue has revolutionized medical diagnosis and is perhaps the
best known use of the technique.
40. Davenal et al, Advances in Magnetic Resonance in Foods (1999) p. 272
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UK SENSING TECHNOLOGIES FOR CONTAMINATION IN FOOD
Figure 12. NMR spectra from beef and horse meat samples, taken from Ref. [41]
Figure 13. Slices of decomposing worm-eaten apple, from Ref. [42]
41. http://www.oxford-instruments.com/
42. http://alisi.isibrno.cz/en/nuclear-magnetic-resonance
OFF-LINE / LAB BASED TECHNIQUES
49
Microscopy
Microscopy uses focused light / electrons to probe very small sample
volumes, scanning electron microscopy for example, boasts a resolution of around 1 nm, as such it is not often used as a alert indicator
for foreign contaminants in food. Its used in food is instead because it
can be used to identify the origin of a contaminant. The origin can be
identified through a range of microanalyses; topological microscopy (by
identifying very small surface marks), and compositional microscopy
(EDAX microanalysis) to identify what the contaminant has been in contact with and through this information, identify where the contamination
has come from.
As an example of the techniques usefulness Figure 14 from Ref. 43
shows a failed weld repair on a tubeplate from a piece of food processing equipment, demonstrating a different metal composition in the
welded area. EDAX microanalysis showed the presence of titanium in
the welded area, absent in the rest of the sample, and indicating that the
wrong welding rod had been used for the repair.
Table 20. Microscopy usefulness in the food sector
PROS AND USES
CONS AND LIMITATIONS
Can be highly specific in terms of
origin of contamination
Can only probe very small
areas so would only be
used once contamination is
suspected
Linked sectors
The highly specific nature of microscopy means that it has many crosssector applications, such as pathology, fundamental science, archeology, forensics etc.
43. Microscopy for the Food Industry, Royal Microscopy Society, Issue 6, 47 (2007)
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Figure 14. A backscattered SEM image of a failed weld repair described in the text.
OFF-LINE / LAB BASED TECHNIQUES
51
Mass spectrometry
In mass spectrometry samples are ionised by high-energy electrons,
the fragments are then separated using a magnetic field to analyse the
spectrum of the weight (m/Z) of the sample. This spectrum is unique
to the sample and can give highly accurate, quantitative information of
contaminant levels in a sample.
An example of where the high sensitivity and high accuracy characteristics of the technique are useful is in allergen testing for allergens such
as egg and milk allergens in baked goods. Traditionally allergen testing
would be done using PCR or ELISA assays, which can suffer from false
negatives and lack a truly quantitative output.
Table 21. Mass spectrometry usefulness in the food sector
PROS AND USES
CONS AND LIMITATIONS
Very specific
Destructive, off-line testing
Resource intensive
Linked sectors
Environmental: Another sector which requires accurate monitoring of
contaminant levels is environmental monitoring
Healthcare: Drug analysis and clinical diagnosis use mass spectrometry techniques to fingerprint the constituent atoms.
Forensics: The unique fingerprinting ability of mass spectroscopy allows accurate identification of substances to be made.
Figure 15. Example of trace analysis of fruit (taken from Ref 44)
44. Screening of agrochemicals in foodstuffs using low-temperature plasma (LTP) ambient ionization mass spectroscopy, Wiley et al, Analyst, 135, 971 (2010)
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Chromatography
Chromatography uses the different speeds in which different substances move through a mobile phase and uses that to separate out the
continuants chemicals. Through this separation the method can provide
quantitative determination of carbohydrates, lipids, proteins, peptides,
amino acids, vitamins, aroma and flavor compounds in a wide variety of
foods and food products (from Ref. 45).
Table 22. Chromatography usefulness in the food industry
PROS AND USES
CONS AND LIMITATIONS
Can be specific in its identification
of contaminant
Sample must be soluble
Quick measurements
Destructive, off-line
technique
Linked sectors
Environmental: Thin-layer and liquid chromatography can detect pollution compounds and pesticides or insecticide residues.
Security: gas chromatography can be used to detect bomb substances, drugs and alcohol
Forensics: can be used to compare fibers found on a victim and analyse the dye composition of fibres, RNA fingerprinting, separating and
testing histamines and antibodies.
45. Cserhati, T. and Forgacs, E. (1999) Chromatography in Food Science and Technology, CRC Press
OFF-LINE / LAB BASED TECHNIQUES
53
Polymerase Chain Reaction
Polymerase chain reaction is a versatile, sensitive and reproducible
process that exponentially amplifies a DNA fragments over several orders of magnitude to test organic material for its make-up. The development of real-time PCR using fluorescence means that information can
be gathered during the amplification process - not only at the end.
Aspects of food quality such as genetically modified organisms (GMOs),
allergens and food authentication are of huge current interest to manufacturers as such real-time PCR is a promising technique for addressing
these. Speed, excellent detection limit, selectivity, specificity, sensitivity
and potential for automation are among the most important advantages
of real-time PCR, Ref. 46.
Table 23. PCR usefulness in the food industry
PROS AND USES
CONS AND LIMITATIONS
PCR test results report very
close to 100 % specificity and
sensitivity.
Can take up to an hour to
receive results.
Offline and destructive
testing
Only applicable for biological
contamination
Linked sectors
Healthcare: PCR is regularly used in medicine for genetic testing, for
screening, tissue typing, mutation monitoring etc.
Forensic pathology: DNA fragments found at crime scenes can be
used to fingerprint uniquely suspects.
46. Rodrîguez-Låzaro, D. (2013) Real-time PCR in Food Science, Norfolk, Caister Academic Press
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Enzyme-linked immunisorbent assay
The enzyme-linked immunisorbent assay (ELISA) is a technique that
uses antibodies and colour change to identify a substance, usually an
antigen but could be an antibody. Common uses of the technique are in
home pregnancy test kits
In the food industry primarily for use in identifying food allergens such
as milk, peanuts, walnuts, eggs etc. In the industry the most common
and preferred methods for detection are ELISA and PCR. The ELISA
method detects the actual allergen protein molecule by binding antibodies to the allergen and ten use enzyme-linked conjugate to create a
colorimetric change, from Ref. 47
Table 24. ELISA usefulness in the food industry
PROS AND USES
CONS AND LIMITATIONS
Non-hazardous equipment
used, unlike other wet chemical
techniques
Expensive
Can detect substances in the
parts per million (ppm) range
Variable quality depending
on skill of tester
Destructive, off-line
technique
Linked sectors
Healthcare: diagnostic tool for pathogens in medicine, such as the HIV
virus.
47. http://www.elisa-antibody.com/index.php?page=food-industry
OFF-LINE / LAB BASED TECHNIQUES
55
ATP Bioluminescence
Adenosine triphosphate (ATP) Bioluminescence is a biological reaction between ATP and the enzyme luciferase that produces light that is
detectable – the intensity of the light is a measure of concentration. ATP
is an indication of life. A pen-like device containing reagents is swabbed
in an area and then inserted into a light monitor. The reading in RLU (relative light unit) is an indication of the presence of organic substances.
ATP bioluminescence is used in the food industry as an indicator of life
and therefore biological contamination.
Table 25. ATP usefulness in the food sector
PROS AND USES
CONS AND LIMITATIONS
Reading within seconds
Destructive testing
Cost effective
Measure only of
microorganism
contamination and
not specific for which
microorganism
Available commercially, doesn’t
require specialist training
Linked sectors
The linked sectors are in any industry where live cell cultures need to be
quantified as perhaps a hygiene concern.
The Knowledge Transfer Network: Food Sensing Report
Technology Summary Table
PCR
OFF-LINE
ELISA
MICROSCOPY
MASS SPECTROMETRY
ATP BIOLUMINESCENCE
ON-LINE
SPECTROSCOPY
X-RAY SPECTROSCOPY
OTHER ON-LINE
CHROMATOGRAPHY
MAGNETIC SEPARATION
X-RAY IMAGING
NEAR IR
OPTICAL SORTING
SAMPLING
METAL DETECTION
VISUAL MONITORING
TECHNOLOGIES OF POTENTIAL
FT-IR
ULTRASOUND
NMR
ELECTRICAL IMPEDANCE
TERAHERTZ IMAGING
HYPERSPECTRAL IMAGING
RAMAN SPECTROSCOPY
BIOSENSOR
MICROWAVE
METAL
HAIR
NATURAL PLANT MATERIAL
WRONG PRODUCTS
RIPENESS
INSECTS
BONE
FAT, GRISTLE ETC
PLASTICS
GLASS (LIQUID)
POTENTIAL TO BE USED
GLASS (PARTICULATE)
CURRENTLY USED
DAMAGE TO FRUITS ETC.
Table 26. Technology versus sensing challenges and their abilities to meet them
CHALLENGES
Challenges
57
Each challenge - either suggested by the UKTI or identified subsequently - is analysed in the following way. Firstly, the challenge is put
in context given its impact on UK recalls, and its potential health and
safety implications. Secondly, the contaminant is analyzed for its physical, chemical and biological properties – this could aid in identifying previously unconsidered techniques for detection schemes. Thirdly, data
from UK manufacturers is used to obtain a general image of how the
challenges is currently being met and finally potential technologies are
listed which may in the future result in new detection systems that can
be employed.
Comments and feedback from either manufacturer questionaires or captured from the workshop in London are incuded in quotation marks.
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1. The detection of glass fragments
– in particulate food
Background
One of the most dangerous contaminations to find in food or drink is
glass; it can cause internal bleeding and even be fatal. Glass fragments
from food factories are occasionally found, for instance from such items
as broken bottles from filling lines, broken fluorescent light tubes and
broken glass viewing panels. Glass was the fourth most complained
about foreign object in food in 2012.
Current situation
The current main methods for detecting glass in particulate food and
liquids with X-rays is that the density of these materials are often very
similar, and as X-ray imaging operates on a density differentiation principle, will fail. Other methods used include visual inspection and sampling, however, the identification of small clear shards that can cause
serious damage, is often non-trivial.
Once contamination is confirmed, then microscopy examinations often
take place. These examinations quantify features such as size, colour,
curvature, surface scratches and deposits. This can be further followed
up by X-ray microanalysis in the SEM. This non-destructive test gives a
spectrum of the elements found in the sample to allow identification of
the likely source of the contamination.
Manufacturers perspective
X-ray imaging
Lab Analytical
29%
29%
Sieving and Sampling
Visual Inspection
21%
21%
Figure 16. Manufacturers current response to challenge
CHALLENGES
59
Contaminant Characteristics
PHYSICAL
Sharp; hard; reflect, refract and transmit light
CHEMICAL
Composed of SiO2
BIOLOGICAL
N/A
Potential for innovation
THz
Proof of principle experiments exist which show how THz imaging can
highlight buried glass in chocolate and meat, Ref [48,49]. With increasing levels of pattern recognition – this could be extended to particulate
food.
Figure 17. (left) THz image of glass in chocolate from Ref. 45 and (right) glass in
meat from Ref. [46]
48. http://www.anteral.com/services/pharma_agri
49. Terahertz imaging spectroscopy for quality inspection in the food industry, Jansen, C. http://www,labint-online.
com
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2. The detection of glass fragments
– liquids in glass
Background
In glass bottled liquids fragments can arise from not only the source
mentioned on the previous page, but also from the bottles themselves.
Monitoring must therefore be performed over the entire production as
glass contamination could occur at any point. Glass was the fourth most
complained about foreign object in food in 2012.
Current situation
The current main methods for detecting glass in particulate food and
liquids with X-rays is that the density of these materials are often very
similar, and as X-ray imaging operates on a density differentiation principle, will fail.
Other methods used include visual inspection and sampling, however,
the identification of small clear shards that can cause serious damage,
is often non-trivial. Once contamination is confirmed, then microscopy
examinations often take place. These examination quantify features
such as size, colour, curvature, surface scratches and deposits. This
can be further followed up by X-ray microanalysis in the SEM. This non
destructive test gives a spectrum of the elements found in the sample to
allow identification of the likely source of the contamination.
Existing technologies for checking glass bottle integrity, such as ‘bottlevision’ are expensive
Manufacturers perspective
X-ray imaging
Optical sorting
29%
Sieving and Sampling
35%
Visual Inspection
18%
18%
Figure 18. Manufacturers current response to challenge
CHALLENGES
61
The detection of small glass fragments within bottled fluids is difficult
Used extensively for soluble coffee granules in Glass Jars. Glass is serious customer complaint. There are still some ‘blind spots’ with X-Ray at
certain points in the glass - would like to eliminate.
Contaminant Characteristics
PHYSICAL
Sharp; hard; reflect, refract and transmit light
CHEMICAL
Composed of SiO2
BIOLOGICAL
N/A
Potential for innovation
ULTRA
Proof of principle experiments exist which show ultrasonic measurements on canned and bottled goods. Restrictions exist in the geometry
of the set-up and impedance matching requirements. But in principle
extra reflections due to foreign bodies are measurable.
Methods for mechanical sepration by spinning the liquid and bringing
the contaminant to the surface
The sound of glass being chipped could serve as a detectable signal
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3. The detection of plastic
Background
Plastics are an increasingly prevalent material of use in the food industry, both in manufacture and in packaging. Plastics were the second
most complained about foreign object in food in 2012. The threats they
pose however are not simply in choking and cutting but also in introducing a chemical and biological hazard to the consumer – depending
on the source. Ultra-high molecular-weight polyethylene (UHMW PE) is
probably the most widely used plastic in food processing facilities and
also is used in conveyor guide rails.
The detection of plastic is a big potential market for detection companies with many seeing it as one of their biggest challenges
Current situation
Currently used methods for plastic detection are visual inspection, optical sorting and X-ray imaging. Identified problems with these techniques are that:
Plastics do not possess the density contrast that metals do, thus making the detection of them with X-rays problematic
Plastics are composed of carbon and oxygen, making the elemental
makeup of the plastic very similar to organic food tissues
The optically transparent nature of many plastics used in the food industry mean that visual inspection can often miss the presence of plastic.
Solutions such as altering the properties of the plastic so that they may
be detected by metal detection / X-ray sources have been trialed. Whilst
seemingly advantageous in terms of ability to retrofit, they are unpopular
for cost reasons, and for the difficulty of getting ‘new’ plastics into the
industry. Additionally, altering process plastics would fail to detect contamination from random events.
Manufacturers perspective
NIR
14%
Metal Detection
32%
13%
X-ray imaging
Optical sorting
9%
Sieving and Sampling
14%
18%
Figure 19. Manufacturers current response to challenge
Visual Inspection
CHALLENGES
63
Filter medium + sieves are used to remove any particulates.
Polycarbonate plastic pieces in moulded chocolate bars. Serious H&S
issues. Huge expense. Detection generally involves retrospective investigation, embargoes etc.
Contaminant Characteristics
PHYSICAL
Largely varying, brittle to flexible, sharp to
rounded, small to large, varying densities
CHEMICAL
mostly composed of complex hydrocarbon
chains, but have a large range of chemical
properties
BIOLOGICAL
N/A
Potential for innovation
METAL
X-RAY
IMAGE
IR
Ordinary plastics cannot be detected by metal detectors however, it has
been suggested that magnetic additives to the plastics used in manufacture could assist in detection – thus utilising one piece of equipment.
Similarly for X-ray detection, inclusion of a heavy element (such as barium) will cause the plastic to fluoresce under X-ray examination.
… clearly however, this relies on the plastic contaminant being identified
and replaced.
Highlighted due to its innate suitability to organic materials and its subtle ability to differentiate foodstuffs from plastics due to the structure of
the sample.
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4. The detection and sensing of fat and gristle
Background
Fat and gristle are very important to the meat industry as they determine
yield. Nobody wants to buy a steak that is mostly inedible. Luckily, fat
and meat tissue have different properties; moisture content, density,
colour etc. and thus can be differentiated.
Current situation
On farms, ultrasound measurements can give important information on
fat and muscle depths, Ref. 50. In processing fat, gristle and meat content in food industries are currently determined by using the difference
in absorption of fat and meat in NIR spectroscopy, NIR relies on the
difference in absorption of different organic compounds and can give
information on key qualities such as texture, juiciness and flavour.
ELISA is used for quantitative analysis of fat content but is an off-line
destructive method. For often, simple visual inspections of the meat are
used to determine fat and muscle content.
There appears to be a large number of approaches to sensing fat, gristle
and cartilage. Most of these techniques are involve moisture detection
– IR, microwave etc.
Manufacturers perspective
NIR
ELISA
30%
Visual Inspection
40%
30%
Figure 20. Manufacturers current response to challenge
Contaminant Characteristics
A comprehensive list of physical, chemical and biological characteristics of muscle, fat and gristle etc are presented in Ref. [51]
50. Improving sheep carcass quality using CT scanning
51. Handbook of Meat, Poultry and Seafood Quality, Leo M. L. Nollet, Wiley (2012)
CHALLENGES
65
PHYSICAL
Difference in colour, texture, spectral response
and water holding capacity to surrounding tissue,
CHEMICAL
Generally insoluble in water, composed of
hydrocarbon chains
BIOLOGICAL
N/A
Potential for innovation
NMR
Academic work using NMR technique has been pioneered for 3D maps
of fat distribution, using an identical set up as that for medical imaging,
Refs [52 and 53]. Mainly for analytical laboratory tests.
HYP
Commercial hyperspectral imaging is currently limited by the somewhat
small sample areas that are illuminated – although breakthroughs have
been made in whole carcass scanning, Ref. [54]
OPT
SORT
Advanced signal processing and machine vision, which can optically
and automatically detect fat by edge detection, would be a applicable
method.
X-RAY
IMAGE
Selection of meat sheep on CT measurements could increase genetic
progress by up to 50 % per annum compared to selection on ultrasonic
measurement [50]
ULTRA
There is ongoing work in the non-contact ultrasound area, via high power ultrasound or photoacoustic imaging. However, the performance of
the detection may not improve significantly on existing equipment, although ultrasound could potentially have uses in whole joints.
52. A. Spyros ad P. Dais, NMR Spectroscopy in Food Analysis, Royal Society of Chemistry (2013)
53. Using Nuclear Magnetic Resonance to Test Fat Content in Foods, Case Study
54. Prediction of Meat Quality: application of hyperspectral imaging and Raman spectroscopy, Moss et al ()
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Figure 21. (left) NMR measurements of different cuts of pork (adapted from Ref. 49)
(right) hyperspectral image of meat with colours corresponding to different fatty
acids from Ref. 51
CHALLENGES
67
5. The detection of bone in meat and poultry
products and in fish
Background
The density difference between meat and bone is small. Rate of “false
positives” can be high – approximately 50 % in some cases, Ref [55].
The presence of bones in food constitutes the fifth highest cause of
complaint in the UK in 2012.
It may also be worth considering the fact that bone in fish and meat is
an ‘accepted risk’ by the consumer, in a fillet of fish one almost expects
to find pin bones in fish and would not naturally consider complaining
– this does not lower the risks associated with them. It may be appropriate to assume the number of incidents associated with fish bones is
in-fact higher than the statistics suggest.
Current situation
The detection technologies for meat and bone for fish meat and poultry
products has largely remained the same for decades, Ref [56]. Automated X-ray systems remain favourites for on-line detection; these systems
are reasonable inexpensive, low maintenance and highly penetrating.
One disadvantage however, is that there are important health and safety
implications to adding an ionising radiation source to a production line.
Visual inspection suffers from not being able to see inside the meat and
so must be used in conjunction with X-ray techniques. However, as is
discussed in the X-ray imaging section – pin bones, cartilage and non
calcified bone tissue is not picked up by X-ray mainly due to their small
size and similar density to surrounding tissue.
Manufacturers perspective
Optical Sorting
X-ray imaging
27%
27%
Visual Inspection
46%
Figure 22. Manufacturers current response to challenge
55. Existing Automated Foreign Body-Detection Systems in the Food Industry
56. Private communication with Campden BRI (2013)
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Contaminant Characteristics
PHYSICAL Various sizes, sharp,
CHEMICAL
BIOLOGICAL
Mainly comprised of calcium phosphate mineral
and collagen
N/A
Potential for innovation
ULTRA
Ultrasonic measurements can be used when there is a large impedance
mismatch in a sample, the implementation of this technique in are and
more in-homogenous substances needs work, Ref [57]
X-RAY
IMAGE
If the sensitivity, accuracy and false positives can be safely negated by
technology advances – it may remain a key technology. New work in
other X-ray techniques aside from conventional X-ray transmission radiography such as X-ray dark-field imaging with a grating interferometer
could advance the technique, Ref [58]
Energy selective X-ray systems (spectroscopy) seem to be the most
sensible approach to do this. This method would allow the different tissues to be identified and has the advantage of being simple and cheap
to retrofit onto existing production lines.
Imaging in the IR regions could work for larger bone fragments, but
would require the product to be flattened out – this may be appropriate
for minced meat, but not for whole fillets.
57. Ultrasound detection and identification of foreign bodies in food products, Food Control, 12, 1 (2001)
58. X-ray dark-field imaging for detection of foreign bodies in food, Food Control, 2, 531 (2013)
CHALLENGES
69
6. The detection of insects in fruits and
vegetables
Background
Most companies regard complaints about insects as one of the most
important. One of the main reasons is the difficulty of detecting and
removing insects and pests (Spiders, bottom-feeders, slugs, snails.) on
a production line, particularly in fresh produce. Pests were the second
most complained about foreign object in food in 2012.
Current situation
The presence of insects can be inferred directly or indirectly with associated signs such as the occurrence of molds and increased mycotoxin
levels in food. There are several used detection methods application
for commodity samples, these are shown on the right hand side. Visual
inspection dominates the detection methodology, it works well for identifying large infestations and the signs of insect presence, but like all visual inspection requiring a human worker it leads to variable results and
high resource usage. Washing and sieving were also answers given as
methods for detection / separating out insects in vegetables and fruit.
Manufacturers perspective
Wash
Optical sorting
19%
Sieving and Sampling
37%
Visual Inspection
25%
19%
Figure 23. Manufacturers current response to challenge
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Contaminant Characteristics
PHYSICAL
Visually different to the food they are in
CHEMICAL
N/A
BIOLOGICAL
Biological in nature, the presence of insects will
leave organic signatures in the food.
Potential for innovation
ULTRA
Ultrasound systems can detect impedance mismatches which can result from insect infestation.
NMR
Has been done for many years on fruit and Ref 37 lists many examples.
Its slow measurement time and high resource cost still make the methods unsuitable for online detection. See Figure 24 for examples.
µwave
THz
HYP
Microwave and THz methods can inspect food for high density and low
density foreign bodies – including insects Refs [59 and 60]
Just as hyperspectral imaging could determine damage to the surface
of an apple, it could also locate the presence of insects.
59. Private communication with Campden BRI (2013)
60. Detection of foreign bodies in foods using continuous wave terahertz imaging, J Food Prot. 75, 179 (2012
CHALLENGES
71
Sound as a means of detecing infestation was mentioned in the workshop – wither through the use of simple mirophones, or listening in the
ultrasonic range.
Electronic noses or other small mass spectrometry-like solutions were
porposed to detect insects by the gasses (smell) they give off. Similar to
the breath analysis techniques for human health monitoring.
Figure 24. NMR images of various fruit Ref. 61
61. http://wellcomeimages.org/
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UK SENSING TECHNOLOGIES FOR CONTAMINATION IN FOOD
7. The quantification of ripeness in fruit
Background
Catching fruit when is about to go bad would cut down on the 10 % of
fruit and vegetables that go bad on store shelves every year, Ref [62].
There are a few indicators in for when fruit is at its ripest, these are a
balance of sugar content and acidity.
Current situation
There are many chemical tests that can determine the levels of the numerous indicators of matureness / ripeness. Currently used methods for
determining the ripeness of fruit include:
•
Brix determination: Brix (oBx) is the sugar content of an aqueous
solution; one degree Brix is 1 gram of sucrose in 100 grams of solution. Ways of measuring Brix include refractometry, NIR and others.
•
Visual inspection involves production workers monitoring the colour,
shape, size etc. to qualitatively determine its ripening stage.
•
The firmness of fruit is often the what is tested by the customer at
the end of the process for optimum ripeness. Industrial processes
do exist for this on the production line – such as a pentrometer.
Acoustic tapping [63], air puff testing.
Manufacturers perspective
Pressure
Optical sorting
23%
31%
BRIX
Visual Inspection
23%
23%
Figure 25. Manufacturers current response to challenge
62. The World Fresh Fruit Market, US Dept. of Ag.(2004)
63. http://www3.imperial.ac.uk/nde/researchthemes/inspection/ultrasound/
CHALLENGES
73
Contaminant Characteristics
PHYSICAL
fruit firmness, colour
CHEMICAL
pH level, sugar content
BIOLOGICAL
N/A
Potential for innovation
ULTRA
Non-destructive acoustic techniques for the measuring the firmness of
fruits may see ultrasound being commercially used.
BIO
SENSOR
Stickers currently exist for certain fruit that measure the aroma of fruit as
it ripens – the stickers change colour to indicate its level of ripeness, Ref
[64].
µwave
Microwave detection Ref [65] uses water content an indicator of ripeness (well distinguished by microwaves) to determine ripeness. The
case of strawberries is shown in Figure 26 (left)
THz
Similar to microwave techniques, Figure 26 (right) shows a leaf that has
been cut and interrogated by THz radiation for water content.
Any method which is sensitive to moisture content; microwave, dielectric spectroscopy, THz, MIR, NMR and NIR.
The combination of detection evidence, ability for packages to modify
atmospheres to slow / speed up ripeness process and the use of prediction algorithms would go a long way to ensuring fruit and vegeatbles
arrive to the consumer at their peak condition.
64. http://www.ripesense.com/ripesense_background.html
65. Robot Learns to Pick the Sweetest, Ripest Strawberries, http://www.wired.com/gadgetlab/2012/08/st_strawberry_robot/ (2012)
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UK SENSING TECHNOLOGIES FOR CONTAMINATION IN FOOD
Figure 26. (a) microwave reflectance image from Ref. 62 (b) THz image of leaf from
Ref. 61
and (c) HSI image of a melon in various stages of ripeness [66]
66. Visualisation of sugar distribution of melons by hyperspectral technique. In: Sun, Da-Wen (ed), Hyperspectral
Imaging for Food Quality Analysis and Control, Chapter 11, pp. 349-368, Academic Press / Elsevier, San Diego,
California, USA.
CHALLENGES
75
8. The detection of damage and mould in fruits
and vegetables
Background
Until about 50 years ago, the spoilage of food by micro-fungi was regarded as a quality issue rather than a food safety concern. Fungal
spoilage of food remains a serious problem, one that has been estimated to account for between 5 % and 10 % of all losses in global food
production.
Damage in fruits and vegetables are also a serious problem, these can
arise through natural causes before the prime producer but also through
improper handling. Unattractive and damaged fruit and vegetables cost
the food industry money in waste and affect consumer confidence.
Current situation
For mould detection, colony count methods require 5 – 7 days to achieve
a result. The interpretation of conventional colony counts can be difficult
requiring considerable staff input.
The respondents to this report highlight the main methods for damage
and mold detection are through visual inspection of the products and
random sampling. It should be noted however that for certain fruit and
vegetables, this rotting can occur inside where visual inspection can
miss.
Manufacturers perspective
Optical sorting
Sieving and Sampling
25%
Visual Inspection
50%
25%
Figure 27. Manufacturers current response to challenge
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UK SENSING TECHNOLOGIES FOR CONTAMINATION IN FOOD
Contaminant Characteristics
PHYSICAL
Damage and mould can affect texture, smell,
water content, shape changes
CHEMICAL
pH change, sugar content change
BIOLOGICAL
EI
µwave
HYP
Growth of mould
Potential for innovation
In Ref [67], electrical impedance measurements were made on an apple
before and after bruising. Distinct resistance changes are observable
Due to the relatively large penetration of microwaves the state of vegetable interiors can be investigated, such as rot inside potatoes, Ref
[68].
Proof of principle work on hyperspectral imaging for bruise detection in
apples, Ref [69]. The reflectance spectrum is characterised by a spectrum change, Figure 28
Key indicators for damage and mould were identified at the workshop
and technologist were encouraged to come up with solutions from
these:
•
Firmness
•
Chemical / VOCs / Pathogen release
•
Discolouration and visual signatures of rot
•
Many of the indicators for ripeness could be used as a prediction
tool for the likeliness of rot.
67. Apple Bruise Detection by Electrical Impedance Measurement, HortScience, 35(1), 104 (2000)
68. Private communication with the NPL (2013)
69. Detection of Bruises on Apples Using Near-Infrared Hyperspectral Imaging, Lu, R., American Society of Agricultural Engineers, 46 (2003)
CHALLENGES
77
Figure 28. Hyperspectral image of apple surface, adapted from Ref 66
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UK SENSING TECHNOLOGIES FOR CONTAMINATION IN FOOD
9. The identification of the wrong product in a
package
Background
Trust in the UK food industry was damaged by the 2012 horsemeat
scandal where traceability of ingredients was not properly observed.
Food adulteration can have huge consequences; the addition of elements that are not included in the ingredient list can have very serious
consequences for allergy sufferers.
Current situation
Ingredient traceability is hugely important – currently to ensure that
things being produced are what they are supposed to be, assurances
from suppliers are relied upon. To prevent large scale recalls and industry confidence damage, a more rigorous approach may be required.
A highly integrated and centralised produce chain where produce elements can be traced back to prime producer through barcoded database approaches is currently a good method for miniminisng mistakes.
However, techniques for actively checking what is going into a product
rely heavily of visual inspection.
Miscoding products was suggested as one of the largest sources of
failure at the end of the packaging line. Wrong shelf life date is a common issue (e.g. 2051 in place of 2015). A lack of universal standards in
machine languages was largely attributed for this.
Short run products (which are commonplace in the chilled food industry)
are most susceptible to this control failure.
CHALLENGES
79
Manufacturers perspective
Traceability and correct packaging is technology area ripe for the picking - Ref [70]
Supplier assurance systems to ensure that ingredient suppliers are controlling their process effectively
Bar Code
Optical sorting
20%
33%
Sieving and Sampling
Visual Inspection
27%
20%
Figure 29. Manufacturers current response to challenge
Potential for innovation
THz
Due to the ability for THz radiation to penetrate plastic and most packaging, contents can be interrogated to ensure the correct things have
been packed.
RAMAN
The non-contact technique of Raman spectroscopy can cheaply and
quickly fingerprint constituents of a product. With references, unexpected adulterations can be removed.
Attendees of the workshop were aware of technologies that could check
the packaging (but not the product) via bar-code readers etc. but the
groups were not informed about industrial adoption of this technology.
There were suggestions that technologies in the NIR or THz area would
be able penetrate the container and product (although not metallised
packaging) and could identify shape using shape recognition software.
Additionally, these techniques have the ability to gather compositional information (protein, fat etc.) however detailed information from the
short wavelength the NIR region is difficult.
70. Private communication with the Cambden BRI (2013)
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10. The detection of “natural plant materials”
Background
Natural products of plant origin can often find their way into food production lines. Extraneous vegetable matter (EVM) are frequently found
to be the case of contaminants in vegetables such as beans or fruits.
Woody materials from the centre of a carrot or parsnip roots or cabbage
stems.
EVM is often of the same composition as the food stuff of interest, as
such analysis of the material for composition will not offer a huge amount
on benefit. If concern is raised about the origin of some unknown EVM
contaminant, the type of material can be identified under microscope
for cell structure - this however, is a resource intensive, off-line method
used once a problem has already been identified.
Current situation
Respondents to this report highlight that the methods currently used are
visual inspect and sieving of the materials. Sieving and separation can
only really be applied at a certain type of foodstuff, whilst visual inspection suffers from varying quality results and high resource use.
Another response was the use of optical sorting methods which use
machine vision and pattern recognition to identify martials that do not
fit the norm.
Manufacturers perspective
NIR
14%
Mass Spectrometry
29%
9%
Optical sorting
Sieving and Sampling
Visual Inspection
24%
24%
Figure 30. Manufacturers current response to challenge
CHALLENGES
81
Contaminant Characteristics
PHYSICAL
Texture, density difference to the surrounding
material
CHEMICAL
N/A
BIOLOGICAL
N/A
Potential for innovation
??
The technology is required to distinguish natural products which are
physically and chemically similar to their surrounding material.
Despite this, some suggestions can be made: improvements to visual
inspection systems would seem a logical solution; benefits may arise
from augmenting optical sorting methods with techniques such as:
•
Vision systems
•
Particle sizing systems
•
Hyperspectral imaging
•
Reflectometry
•
Capacitance tomography
•
Dielectric spectroscopy
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11. Hair and fibre contamination
Background
Finding hair in food can be one of the more upsetting incidents for a
consumer. The source of the hair is often from human intervention – and
while these incidents are high on the HAACP agenda and various methods of prevention are in existence (hair nets, ban on beards, gloves etc.)
the discovery of hair rarely prompts a recall due to the randomness of
the event
The presence of rodent hair may be an indicator of rodent infestation at
some point in the food chain. Sources of artificial fibres can be bristles
from brushes, twine from factory sacks, woolen fibres from clothing.
The exact identification of these can be made using FT-IR, Ref. [71]
Current situation
Hair presents a huge challenge for X-ray inspection technology, its low
density and very small (10 – 200 µm) dimensions make it always impossible to detect in small quantities. Simply put, the prevention of the hair
ending up in the process will be easier than detecting it as a contaminant.
Contaminant Characteristics
PHYSICAL
Small 10 – 200 µm, high tensile strength
CHEMICAL
Mostly composed of keratin, high concentration
of cysteine, can carry distinctive chemicals from
product
BIOLOGICAL
N/A
Potential for innovation
Technologies are suggested which are not sensing solutions used to
detect the hair itself, but instead non-compliance with procedure (analogous to hand washing solutions in healthcare). For example, an optical sensing system to monitor whether hairnets are being sed correctly
could be used to flag an alarm of non-compliance.
71. Foreign body complaints in the food ad drink industry, Newfood Magazine, Issue 2, Page 9 (2013)
CHALLENGES
83
12. The detection of metal of any sort of food
product
Background
Despite the fact that metal detection is one of the most common and
oldest forms of foreign object detection – it remains a large cause for
concern in the food industry. Indeed, from 2006 – 2012 physical contamination from metal has increased its proportional share largely whilst
the total number of incidents has not changed significantly. The reason
for this increase of the 6 year period is unclear.
European Frameworks exist to limit the amount of metals in food and
drink in the EU, heavy metals such as cadmium, lead, arsenic etc. are
present in the environment and if ingested can build up and cause serious health problems in living organism.
Metals in food industry process are intentionally used for their hardness,
often found contaminants are large objects, nuts from machinery, shot
from shotgun, metal wool, sieve components etc. These large objects
have the ability to cause a choking hazard, damage the inside of an
organism or break teeth.
Current situation
Metal detection systems are ubiquitous in food manufacturing plants which must make the continuing hazard posed by incidents extremely
frustrating for manufacturers. Energy dispersive X-ray analysis is a quick
and non destructive method that can be used on metals, often performed in conjunction with microscopy techniques - this combination
can reveal evidence on the course of contamination once a contamination has been identified but is currently not an in-line technique.
Technologies need to be adaptable for new materials introduced to supply lines, titanium, stainless steels, almunium and other lightweight metals.
Contaminant Characteristics
PHYSICAL
Sharp, electrically conductive, can be magnetic
CHEMICAL
Wide range of chemical properties
BIOLOGICAL
N/A
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UK SENSING TECHNOLOGIES FOR CONTAMINATION IN FOOD
Potential for innovation
A seemingly satisfactory solution might be in improving the performance
/ expanding the capabilities of current technologies. For example, energy selectivity X-ray detectors could be retrofitted onto existing lines
for the identification of metals.
Methods for monitoring dielectric properties of contaminated foods
were discussed as a possible solution, given that metal would have a
noticeably different signature to surrounding material.
CHALLENGES
Conclusions
85
The key challenges identified are extremely varied in their requirements
– no one technology will solve all of these challenges. A large number of
the techniques available have the potential to be able to ‘fingerprint’ a
contaminant. These are either chemical techniques (mainly off-line) but
also spectroscopic techniques based on the scattering and absorption
of different parts of the electromagnetic spectrum.
Communication with UK manufacturers highlight the needs of the commercial food manufacturing sector in these areas. The manufacturing
sector requires:
Seeking in-line methods, which reduce number and frequency of tests.
We are always very keen to use non-destructive techniques so we can
reduce waste levels generated during testing
Identified areas of concern are those where detection methods are
based on either:
Visual inspection or assurance systems that ingredient suppliers are
controlling theirprocess effectively.
There is also an ongoing trend away from traditional X-ray imaging due
to health and safety concerns and the success rate of X-ray machines.
Key identified challenges where either the complaints remain too high or
where innovative technologies couldn’t be adequately found are:
•
Glass in bottled liquids
•
Metal in food and drink
•
Plastics in all food
•
Pin bones, cartilage and non-calcified bone tissue.
Various technology areas have been looked at for this report with communication with consultants and national laboratories. These technology areas can be split into two categories; areas which have been developed but are not applied in this sector and areas which are at a lower
readiness level.
Non-commercial / emergent technologies:
THz: longer wavelengths than traditional light source allow the depth
of penetration to be increased. This may have the advantage of looking
into sealed packages, and water concentration monitoring for a variety
of purposes. Overly expensive and low technology readiness equipment mean that the roll out of these devices is a way off.
Hyperspectral: whilst there do exist some commercial technologies,
the wide scale roll out of these has not yet been achieved. Technology
does however exist and is becoming more available on the commercial
market. The wide range of contaminants able to be sensed makes this
an attractive technology.
Ready in linked sectors
Microwave: The technologies exist for detection and production of microwave radiation, and indeed much research is currently being done
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UK SENSING TECHNOLOGIES FOR CONTAMINATION IN FOOD
on the uses of this in the food sector
X-ray techniques: the food sector has benefited greatly from the use
of X-rays, although going out of favour, advances in sensitivity and tomographic approaches continue to make X-ray imaging and attractive
option
Biosensors: becoming highly prevalent in the medical and environmental markets, it is assumed that if they can be made to fit the industry
needs, they will make good progress in the food market also – although
their limitations to off-line techniques make the implementation of these
difficult.
Raman: Raman is making important inroads into many sectors, healthcare, environmental monitoring. Whether it can fit into the food market
by covering the important challenges detailed remains to be seen [72].
Ultrasound: well known in NDE circles the application of ultrasound to
the food and drink sector is not well developed, key to its exploitation is
furthering is ease of application and quantifying the limits of detection
it can offer.
Linked sectors: There are a number of linked sectors whose input could
increase the rate of pull through for many of these challenges:
1. Healthcare: advanced biosensors are being developed for disease
detection which could be linked
2. Defence and Security: detecting things that should not be there is
a goal of defence and security. Many technologies used there are
applicable in the foreign body sensing world
3. Material science: many limiting factors in the spectroscopy methods are closely related to the high price of source and detector
technology. For example fast and accurate multispectral CCDs are
not cheap, disruptive advances in this area would help
Barriers to innovation
There are however inhibiting factors to innovation in this sector; food
industry representatives are often looking for better versions of what already exists. Engagement events are key to exposing the up and coming technologies to food industry representatives to technology areas
outside of their own areas of expertise and sector.
Although a huge industry, the food industry can be very conservative in
the adoption of new technologies and it can require much higher rates
of return on capital investment than can be delivered, therefore the food
industry seeks low- cost solutions that can justify the effort. The idea
that product recalls can be reduced or prevented by better training,
procedures etc. is a far more appealing alternative to large R&D investments.
72. Note on spectroscopy: whilst the detection of what is inside our food is obviously an important goal for manufacturers, there may be concern from manufacturers about the level to which technology is able to do this. The ability
to reverse engineer expensive and complex food and drink will likely not be well received by the manufacturing
community.
APPENDIX 1
Appendix 1. UK
capabilities
in highlighted
areas
87
The UK capability in relevant areas has been assess on the basis of
conclusions drawn from Appendix 3: RCUK Grant Analysis. The grants
awarded with keywords as any of the identified technology areas are
analysed for their Technology Readiness Level (TRL), the activity in the
Research Councils and the relevance the technology has to the food
sensing sector. See Table 27 for results.
Identified technologies areas with a high relevance to food sensing; ultrasonics, hyperspectral and
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Table 27. RCUK Technology Capability Analysis
TECHNOLOGY
CATEGORY
KEY INSIGHTS
REPORTED
ACTIVITY LEVEL
RELEVANCE OF
TECHNOLOGY
CATEGORY FOR
SECTOR
• Large spread of addressed sectors
TERAHERTZ
• TSB money is funded heavily to one
company
• Primarily funded at the EPSRC level,
where sources and detectors are the
focus
HIGH
MED
HIGH
HIGH
LOW
HIGH
MED
HIGH
MED
MED
LOW
MED
HIGH
LOW
• Many TSB grants in the food sector here
• Unsurprising amount of grants from
MRC
ULTRASONIC
• Focuses on imaging applications
• Wide range of disciplines using
technique
• Developments in medicine are to rival
traditional imaging, drug delivery
• HVM applications, defects, joints etc.
HYPERSPECTRAL
INFRARED
TECHNIQUES
• A large number of these proposals
come from one company, M-Squared
Lasers
• Funding majorly into Earth Observation
and space missions.
• Number of biological projects funded
• Space technologies funded in the IR
areas
• Space and EO applications
RAMAN
• TSB funded only a few companies
• Medical and biological charactisation
• STFC funded projects for niche product
development for UK Mars missions
CAPACITANCE
/ IMPEDANCE
TOMOGRAPHY
• Slim pickings
• Interesting spread of applications
• Big funding for biosensor networks for
sports
BIOSENSORS
• Large programmes
• Well covered across all RCUK
• Some for the food chain
• Strong funding for medical
APPENDIX 1
89
Each of the selected technology areas identified in the report and workshop discussions have been analysed in terms of the UK Research
Councils grant funding aimed in those areas [73]. The relevant projects
are extracted, an estimated technology maturity level (TML) of the project assigned to them and graphed.
TML 1
PROBLEM
IDENTIFIED
TML 2
PRINCIPLE
UNDERSTOOD
TML 3
PROOF OF
CONCEPT
TML 4
REALISTIC
DEMONSTRATION
TML 5
SYSTEM
PROTOTYPE
TML 6
NICHE
PRODUCTION
TML 7
MASS
PRODUCTION
Problem identified – academic,
basic principles being questioned
Principles understood – academic
exploration, understand associated
physics early level experiments to
validate theories. Development of
underlying components
Proof of Concept – academic, can
the device function as required
Realistic Demonstration at
commercial level, can the device
function in a realistic scenario
System Prototype, commercialise.
Does the product exist as a
assembled, integrated prototype
Niche Production, is the project
going into niche production
Mass Production, is the product
going into mass production
Care was taken to identify projects where only technology advancement in the technology area was the purpose of the project and from
the public description (if available). The TML was estimated using the
following criteria:
The resulting graphs give an indication as to would stage the UK research in that technology area is at, and what research councils are
currently funding it. Key insights from the project descriptions are attempted to add to the graphs and a diagram of keywords is presented
at the end of each technology section [74].
The geographical spread of academic groups involvedin the RCUK
grants and any industrial partners are included to highlight areas of excellence.
73. Data extracted from http://gtr.rcuk.ac.uk (only projects post 2006 are included)
74. Images formed using http://www.wordle.net
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UK SENSING TECHNOLOGIES FOR CONTAMINATION IN FOOD
TSB
Technology Strategy
Board
STFC
Science & Technology
Facilities Council
NERC
Natural Environment
Research Council
MRC
Medical Research
Council
ESRC
Economic and Social
Research Council
EPSRC
Engineering and
Physical Sciences
Research Council
BBSRC
Guide to the Research Councils
Biotechnology and
Biological Sciences
Research Council
AHRC
90
Arts and Humanities
Research Council
APPENDIX 1
91
Terahertz
Terahertz technology is an emergent technology, as such, all instances
of THz radiation being used in a research project is included in this
survey. It is concluded in Ref. [75] that there is a full supply-chain with
system, subsystem, component and material suppliers in the UK for
THz radiation - Teraview Ltd is one of the world’s leading suppliers of
commercial equipment for close-in active imaging and spectroscopy
at THz frequencies. Thruvision (Oxford) manufacture security screening
products which detect passive Terahertz radiation from the surroundings. Other UK companies involved in THz are M- Squared Lasers who
manufacture THz laser sources based on ultrafast pulse lasers, QMC
Instruments Ltd, which manufactures instrumentation and Teratech
Components Ltd (THz electronics). e2v technologies are suppliers of
low-THz Gunn diode components and mixer/amplifier subsystems, and
the University of Manchester are commercial suppliers of GaAs-based
epiwafers through a subsidiary company. There is also a significant tail
of specialised microwave sensing groups like Navtech Ltd which integrate systems for defence and security applications at lower frequencies, but are potential entrants at higher frequencies.
Academic groups like those at Cambridge, St Andrews, Leeds, RAL,
Essex, UCL, QMC, Cardiff, and Manchester cover the full range of “optical sources”, “solid-state microwave-sources” and detectors for THz,
with system integration, whilst the STFC facilities at Daresbury, and associated academic groups provide a full supply chain for “vacuum electronic tube” sources for THz at higher powers.
Key words
“THz” or “Terahertz”
Statistics
AHRC
BBSRC
EPSRC
ESRC
MRC
NERC
TSB
STFC
1
0
55
0
0
0
4
4
Number of funded projects in this area since 2006
64
Number of live projects
31
75. Roadmap: UK III-V Community Engagement with Industry, ESP-KTN (2012)
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UK SENSING TECHNOLOGIES FOR CONTAMINATION IN FOOD
TML Analysis
35
Total
30
TSB
25
STFC
20
NERC
15
MRC
Terhertz
Diodes resonant
electron
painting
Systems
Devices
Substrates
exploiting
T-Ray Advanced
surgery
Fibre-Based Quantum
Novel
brightness
EMISSION
Planar
far
beams
Fast Thermal
controlling
Temperature
relativistic
Coherent
Imaging
generation AMPLIFIERS
Cascade
pseudospark-sourced
innovative processes
Tomography
Electroniic
probe InP
SEMICONDUCTOR
multi
10
ESRC
5
EPSRC
0
TML 1
TML 2
TML 3
TML 4
TML 5
TML 6
TML 7
BBSRC
AHRC
Key Insights
• Large spread of addressed sectors
• TSB money is funded heavily to one company
• Primarily funded at the EPSRC level, where sources and detectors
are the focus
Total RCUK Funding: £ 33,177,105
APPENDIX 1
93
Map of RCUK academic (yellow) and industrial (red) grant receivers. The locations are approximate and the size of the circles
represent the number of grants at that institution
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UK SENSING TECHNOLOGIES FOR CONTAMINATION IN FOOD
Hyperspectral
There are various UK companies working at various points in the supply chain for HSI equipment; a notable company is Gilden Photonics
which in partnership with the University of Strathclyde, Hamamatsu and
Specim run the Hyperspectral Imaging Centre.
There are strong groups of research in HSI in the UK with applications
covering many sectors such as food and agriculture, homeland security and medicine. Universities such as Strathclyde, Glasgow, Cranfield,
Manchester, Birmingham and Leicesterare active in fundamental technology research (detection and signal processing)
Key words
“Hyperspectral” , “HSI” or “multispectral”
Statistics
AHRC
BBSRC
EPSRC
ESRC
MRC
NERC
TSB
STFC
1
0
1
0
0
1
5
7
Number of funded projects in this area since 2006
16
Number of live projects
6
APPENDIX 1
95
TML Analysis
6
Total
5
Camera
WAVE system
oil
optical suppression
Offshore
remote
instrument
lifetime
Active
oscillator
sensing
Long
techniques
Laser-based
wastes
applications
hyperspectral
measurement
biogenic
SKYDOME
TSB
4
STFC
3
NERC
2
MRC
ESRC
1
EPSRC
0
TML 1
TML 2
TML 3
TML 4
TML 5
TML 6
TML 7
BBSRC
Figure 31. TML for HSI RCUK projects
AHRC
Key Insights
• A large number of these proposals come from one company,
M-Squared Lasers
• Funding majorly into Earth Observation and space missions.
Total RCUK Funding: £2,709,295
remote
fluorescence USING
disease
development
examination archaeological
optical VIS-IR
Harmonic
Active
portable
gas
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UK SENSING TECHNOLOGIES FOR CONTAMINATION IN FOOD
Map of RCUK academic (yellow) and industrial (red) grant receivers. The locations are approximate and the size of the circles
represent the number of grants at that institution
APPENDIX 1
97
Capacitance
and electrical impedance tomography
Key words
“capacitance tomography”, “capacitance imaging” ,“impedance
imaging” and “impedance tomography”
Statistics
AHRC
BBSRC
EPSRC
ESRC
MRC
NERC
TSB
STFC
0
0
3
0
1
1
0
1
Number of funded projects in this area since 2006
6
Number of live projects
3
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TML Analysis
4.0
Total
3.5
TSB
3.0
STFC
2.5
2.0
NERC
1.5
RIVER
sensor
viability
Ultra-fast
Early Magnetic
plc
measurement feedback
electrical
intervention
thrombolytic
pharmaceutical
imagine
morphology EIT
particulate
Resonance
tomography
measurement
impedance
GAS-SOLID
control
Complementary stroke
viability
fluidised
complex
distribution
Bath Array
Magnetic
industrial
acute
granule
MRC
1.0
ESRC
0.5
EPSRC
0.0
TML 1
TML 2
TML 3
TML 4
TML 5
TML 6
TML 7
BBSRC
Key Insights
AHRC
• Slim pickings
• Interesting spread of applications
Total RCUK Funding: £1,546,203
APPENDIX 1
99
Map of RCUK academic (yellow) and industrial (red) grant receivers. The locations are approximate and the size of the circles
represent the number of grants at that institution
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Biosensors
For a detailed analysis of the UK capabilities in biosensing refer to Ref.
[38]. The UK has a strong commercial biosensors community – however
it is highly focused in medicine and healthcare markets, and so is limited in its responsiveness to other opportunities. Existing institutions,
for examples the CPI / Medtech KTN / Biosensors KTN and existing
industry/academic collaborations such as the Cambridge IKC etc. can
facilitate the pull- through. Nationally funded programmes by groups
like the Environmental Agency (EA), NERC and MOD also provide some
pull-though into demonstration for specific technologies in niche applications. Both MOD (via the Centre for Defence Enterprise) and NERC
are active in seeking to build commercial impact from this research.
The UK boasts a strong academic capability in biosensing research with
worldclass research instutions such as at the Universities of Exeter, Cardiff, Bristol, Reading, Oxford, London, Southampton, Cambridge, Cranfield, Manchester, Durham, Newcastle and Belfast.
Key words
“biosensor”
Statistics
AHRC
BBSRC
EPSRC
ESRC
MRC
NERC
TSB
STFC
0
11
12
0
1
2
0
8
Number of funded projects in this area since 2006
34
Number of live projects
11
APPENDIX 1
101
TML Analysis
20
Total
TSB
15
STFC
10
DRUGS
Active
circuits
MRC
WHOLE-CELL
5
biosensing
ESRC
synthetic
plc
micro-chemostat MRSA
detection
piezoelectric
warning
EPSRC
0
pharmaceutical
spectrum
engineering GENE
explosives
NERC
chemical
biosensor
ultra-sensitivity
waveguide
TML 2
TML 3
TML 4
TML 5
TML 6
TML 7
BBSRC
AHRC
Key Insights
• Big funding for biosensor networks for sports
• Large programmes
• Well covered across all RCUK
• Some for the food chain
Phage
self-regenerating
MATERIAL
TML 1
Total RCUK Funding: £ 14,467,904
Film
Polymer
development
cell
monitoring
Bulk Acoustic
rapid
synthetic
broad
advanced
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Map of RCUK academic (yellow) and industrial (red) grant receivers. The locations are approximate and the size of the circles
represent the number of grants at that institution
APPENDIX 1
103
Ultrasonic
According to the Cohort Study by the ESP Sensors and Instrumentation
group, Ref [76] – there are 126 UK groups developing or distributing
ultrasonic sensors, sub-systems or instrumentation with large interests
in sectors such as aerospace and defence, automotive, building, energy
and security- but very little in the agriculture sector (where food would
lie in the classification system of the study). Some companies such as
Mainstream Measurements, Hach Lange provide ultrasonic solutions
for environmental monitoring for pipes which could be applicable to
food technologies.
The UK hosts many groups working in the field of NDE using ultrasonics, Strathclyde, Warwick, Leeds and Bristol. The research activities are
varied due to the large cross-applicability of the technique. The activities include research into materials stress and damage for construction,
NDE for pipes, transport infrastructure etc.
Ultrasonics is a well-established technique in NDE, for the purposes of
this assessment, projects were analysed which:
Applied the technique in unknown configurations
Used in conjunction with other techniques to extract new information
Develop novel process design, sensor design.
Projects are NOT included which use the technique as a tool in standard configurations.
Key words
“Ultrasound” or “ultrasonic”
Statistics
Number of funded projects in this area since 2006
135
Number of live projects
42
AHRC
BBSRC
EPSRC
ESRC
MRC
NERC
TSB
STFC
0
12
81
2
8
0
11
0
76. Cohort study of the Commercial Sensors and Instrumentation community of the UK, to be published 2014. ESP
KTN
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UK SENSING TECHNOLOGIES FOR CONTAMINATION IN FOOD
TML Analysis
60
Total
50
microbubbles
NDE
development
Arrays Non-Detructive
techniques
gene
sonotweezers
imaging New
Structures
lasers
biosensor
Real
using
NON-CONTACT
Automated
rye-grass
development
TIME monitoring
gun Sound
joints
surface
components
intensity
30
NERC
20
MRC
ESRC
EPSRC
TML 1
TML 2
TML 3
TML 4
TML 5
TML 6
TML 7
BBSRC
AHRC
Key Insights
• Many TSB grants in the food sector here
• Unsurprising amount of grants from MRC
• Focuses on imaging applications
characterisation •
nonlinear
STFC
0
Tomography
material
application CANCER
40
10
monitoring
processes
TSB
Wide range of disciplines using technique
• Developments in medicine are to rival traditional imaging, drug
delivery
• HVM applications, defects, joints etc.
Total RCUK Funding: £58,073,043
APPENDIX 1
105
Map of RCUK academic (yellow) and industrial (red) grant receivers. The locations are approximate and the size of the circles
represent the number of grants at that institution
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UK SENSING TECHNOLOGIES FOR CONTAMINATION IN FOOD
Infra-red Techniques
Infrared techniques have been used for many years in many technology,
for the purposes of this assessment, projects were analysed which:
Applied the technique in unknown configurations
Used in conjunction with other techniques to extract new information
Develop novel process design, sensor design.
Projects are NOT included which use the technique as a tool in standard configurations.
Key words
“FTIR” or “IR” or “NIR”
Statistics
AHRC
BBSRC
EPSRC
ESRC
MRC
NERC
TSB
STFC
1
0
10
0
0
1
1
7
Number of funded projects in this area since 2006
20
Number of live projects
8
APPENDIX 1
107
TML Analysis
8
Total
7
TSB
6
STFC
5
4
NERC
3
spectroscopic
EChO
2
ESRC
antibodies
Miniature
Optical Telescopes
Leak
Nanoparticles
FTIR
imagingfocal-plane
MRC
1
EPSRC
0
Astrophysics
TML 1
TML 2
TML 3
TML 4
TML 5
TML 6
BBSRC
Sensors
Detector
Spectrometer POLYMER
Applied
Transform
Enzyme
TML 7
AHRC
Key Insights
• Number of biological projects funded
• Space technologies funded in the IR areas
simultaneous
Technology
Total RCUK Funding: £7,054,841
New
therapeutic
low cost
camera
SUPPORT heritage
brain Gas
Fourier
Petrochemical
skin
free-space
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UK SENSING TECHNOLOGIES FOR CONTAMINATION IN FOOD
Map of RCUK academic (yellow) and industrial (red) grant receivers. The locations are approximate and the size of the circles
represent the number of grants at that institution
APPENDIX 1
109
Raman
Raman spectroscopy is a well-established technique for material characterisation, for the purposes of this assessment, projects were analysed which:
Developing the technique in unknown configurations
Used in conjunction with other techniques to extract new information
Develop novel process design, sensor design, enhancing Raman signal
with SERS
Designing new sources, sensors, analytical methods
Projects are NOT included which use the technique as a tool in standard configurations for characterisation.
Key words
AHRC
BBSRC
EPSRC
ESRC
MRC
NERC
TSB
STFC
0
7
17
0
3
4
6
23
Number of funded projects in this area since 2006
60
Number of live projects
28
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UK SENSING TECHNOLOGIES FOR CONTAMINATION IN FOOD
TML Analysis
15
Total
TSB
12
STFC
9
NERC
6
MRC
Glycan
biologically
EYE
Stem cells
lidar
microscopy
Lipid
PAT
proteinpollutants
ESRC
3
EPSRC
0
TML 1
TML 2
TML 3
TML 4
TML 5
measurements
dissolution
SERS
Live Anti Exomars
tool
Mars
Procurement
Evaluation
Simple
gas-phase
non-invalve
species
REALISTIC Urban
disease RLS
Nanosensing
monitoring
boundary
Scattering
TML 7
BBSRC
Strokes
nanoparticle
TML 6
AHRC
Key InsighTS
• Space and EO applications
• TSB funded only a few companies
• Medical and biological charactisation
• STFC funded projects for niche product development for UK Mars
missions
Total RCUK Funding: £13,700,211
APPENDIX 1
111
Map of RCUK academic (yellow) and industrial (red) grant receivers. The locations are approximate and the size of the circles
represent the number of grants at that institution
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UK SENSING TECHNOLOGIES FOR CONTAMINATION IN FOOD
Appendix 2:
Inputs into
the February
Workshop
NAME
Moses Ajayi
Gordon Attenborough
Nicholas Bantin
Simon Baty
AFFILIATION
University of Lincoln
The IET
IS – Instruments
Bioscience KTN
Devaki Bhatta
Labxero
Matt Butchers
ESP KTN
Andrew Condie
Marianne Defernez
Roger Dewell
Photonics Analytics
Institute of Food Research
Interasight
Geoff Diamond
Inspection Technologies
Rachel Hackett
Greencore Group
Gabriel Hamid
Victoria Hammond
Theresa Huxley
Ken Johnston
Bühler Group
Smith and Nephew
Sainsburys
UKTI
Henry Langston
Ocean Optics
Mark Littlewood
ESP KTN
Neil Loxley
Ibex Innovation
Ellen Ni Cleirigh
Nestle
Malcolm Povey
University of Leeds
John Roberts
Richard Seager
Adrian Stevenson
Nigel Stewart
Shobitha Sundararajar
Richard Turner
Jill Webb
Sharp Electronics
Marel
Labxero
AC Goatham
Photek
University of Lincoln
Leatherhead Food Research
APPENDIX 2
113
Trevor Whittley
Martin Whitworth
Fibre Photonics
Campden BRI
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UK SENSING TECHNOLOGIES FOR CONTAMINATION IN FOOD
Appendix 3:
Acronyms
2D
Two-dimensional
3D
Three-dimensional
AHRC
BBSRC
Arts and Humanities Research Council
Biotechnology and Biological Sciences Research Council
ATP
Adenosine triphosphate
CCD
Charge Coupled Device
CT
Computed Tomography
DNA
EA
Deoxyribonucleic acid
Environment Agency
EDAX
Energy Dispersive X-ray Analysis
ELISA
Enzyme-linked immunosorbent assay
EM
Electromagnetic
EO
Earth Observation
EPSRC
ESRC
Engineering and Physical Sciences Research Council
Economic and Social Research Council
EVM
Extraneous vegetable matter
FSA
Food Standards Agency
FT-IR
H&S
HACCP
HSI
IR
Fourier transform infra-red
Health & Safety
Hazard Analysis & Critical Control Points
Hyperspectral Imaging
Infra-red
KTN
Knowledge Transfer Network
MIR
Mid Infra-red
MOD
Ministry of Defence
MRC
Medical Research Council
MRI
Magnetic Resonance Imaging
APPENDIX 3
115
MRSA
NDE
NERC
NIR
Methicillin-resistant Staphylococcus aureus
Non-destructive evaluation
Natural Environment Research Council
Near infra-red
NMR
Nuclear magnetic resonance
PCR
Polymerase chain reaction
PoC
Point of Care
R&D
Research and Development
RADAR
Radio detection ad ranging
RCUK
RF
UK Research Councils
Radio frequency
RGB
Red Green Blue
RLU
Relative Light Unit
RNA
Ribonucleic acid
SERS
SONAR
STFC
Surface Enhanced Raman Spectroscopy
Sound navigation and ranging
Science and Technology Facilities Council
TML
Technology Maturity Level
TSB
Technology Strategy Board
UAV
Unmanned Aerial Vehicle
UK
United Kingdom
UKTI
UK Trade & Investment
VOC
Volatile Organic Compounds
WHO
World Health Organisation
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UK SENSING TECHNOLOGIES FOR CONTAMINATION IN FOOD
About The
Knowledge
Transfer
Network
The Knowledge Transfer Network spans the technologies underpinning
devices, tools and technologies that are taken for granted today—and
that will be taken for granted tomorrow.
We are committed to connecting people who don’t usually meet because that’s where the magic happens. Whether this means farmers
talking to sensors specialists about sustainable agriculture; or materials
scientists talking to laser scientists about 3D printing—we exist to put
innovation into practical use
APPENDIX 3
117
The Knowledge Transfer Network: Food Sensing Report
Knowledge
Transfer
Network
Knowledge
Transfer
Network
MATT BUTCHERS
[email protected]
MARK LITTLEWOOD
[email protected]
SIMON BATY
[email protected]