Nanowatch
© 2013. This article is reproduced by permission from
Global Business Briefing www.chemicalwatch.com
Test methods for food ingredients
A US research project is trying to develop testing methods and a safety assessment
methodology for food additives made with nanotechnologies
The debate over the appropriate testing to
demonstrate the safety of nanoscale food
additives is more than a decade old, and
we have yet to see the full evaluation of an
engineered nanomaterial for use in food.
Guidance on the risk assessment of
nanoscience and nanotechnology
applications to food and feed, which
provides a systematic decision route to risk
assessment with guidance on the types of
tests and methods that may be required for
physico-chemical characterisation and
toxicological evaluation of nanomaterials
in food and feed products, was published
by the European Food Safety Authority in
2011. But regulators in the US and EU have
not yet described specific testing methods
for nanomaterials. Instead, their approach
to regulatory testing and decision making
is based on the active review of regulatory
submissions. This can create an atmosphere
of uncertainty regarding safety, and can be
used to paint regulators as out of touch
with current technology and the safety
concerns raised by that technology.
The EU food additives Regulation
(1333/2008) established the periodic
re-evaluation of additives that are
produced by a process, or from starting
substances, which significantly differ from
the ones approved. A new risk assessment
is required for already authorised additives
if there has been a “significant change in
the production methods or in the starting
materials used, or if there is a change in
particle size, for example through
nanotechnology”. This provision requires
the review of an already approved additive
if it was produced in the nanoscale.
Addressing safety
What may be the first comprehensive
effort to develop practical tools to address
the safety of nanomaterials from the
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standpoint of regulatory decision making,
has been established in the US. The
NanoRelease food additives project,
organised by the International Life
Sciences Institute, is a public-private
partnership including representatives from
the US and other governments, academia,
private foundations and industry, working
to address the fundamental questions
regarding the safety of food ingredients
The approach of
regulators in the US and
EU to regulatory testing
and decision making
is based on the active
review of regulatory
submissions. This can
create an atmosphere of
uncertainty
manufactured using nanotechnology. The
project seeks to identify and develop
testing methods to probe the safety of
“nanomaterials”, and to simultaneously
define “nano-based” factors clearly linked
to the safety of the materials.
The project participants have drawn on
published and unpublished information,
and knowledge of the participating
experts. A focus is to map necessary testing
to identify whether a material that is
ingested is taken up in a nanoscale form,
which might raise novel safety questions.
From this consideration, the project
participants will identify gaps in scientific
knowledge that must be bridged in order
to make that testing a reality. The
participants will then produce plans for
methods development to address critical
knowledge gaps and to develop a widely
accepted methodology for probing the
Global Business Briefing / May 2013
safety of nano food additives.
Physical and chemical
attributes
Task groups were established to address
critical questions for safety assessment. The
first task group on material characteristics
focused on knowledge of nanomaterials
used in food matrices, with respect to their
ability to be absorbed into the body. The
group considered the physical and chemical
attributes of nanomaterials and the physical
and chemical properties of the food
matrices separately, and developed a
catalogue of the types of nanomaterials in
the food supply. In addition, the task group
characterised properties broadly as they
relate to the physical structure and form of
the nanomaterial and the surface reactivity
and binding characteristics of the
nanomaterial. Characteristics of importance
for metal and metalloid particles include
the concentration and chemical
compositions in food matrices, as well as
the size and surface area, shape, crystal
form and surface charge. The characteristic
deemed most important for lipid
encapsulates was size, especially in relation
to the bioavailability of the encapsulated
material. For other nanomaterial particles,
zeta potential, morphology, size, solubility
characteristics (especially hydrophobicity)
and the presence of targeting agents were
deemed most important. Uncertainties
regarding characterisation include the point
in the lifecycle of the material at which
characterisation needs to take place, as well
as the scale by which to characterise such
properties as size, digestibility and shape.
Knowledge-centred approach
The task group focused on knowledge of
the environment of the alimentary canal
and the various pathways by which a
nanomaterial can be taken up and pass in
to circulation within the body, and
biological barriers that can block uptake,
as well as the metabolic processes that can
alter and “detoxify” the nanomaterial and
facilitate its elimination from the body. The
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group concluded that models and tests are
needed to address the differing
characteristics of multiple points along the
digestive tract, including the properties of
different cell types and fluid environments.
In addition, the group noted the
importance of considering the potential
impact of differing conditions related to
developmental stage and disease state that
can affect uptake.
The third group considered models
relevant to the alimentary canal for the
quantification of nanomaterial behaviour.
Overall, the group concluded that relevant
models do exist. The group concluded that
these screening methods could also be
adapted to model disease states or other
population sensitivities. The task group
also decided that existing OECD protocols
for evaluating oral exposures were
adequate when needed to evaluate higher
exposure nanomaterials, but the
alternative screening models proposed will
require substantial validation.
The fourth group considered the requirements
for, and the availability of, methods to detect
and characterise nanomaterials as pristine
materials, and in the context of food and
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© 2013. This article is reproduced by permission from
Global Business Briefing www.chemicalwatch.com
biological matrices. The group identified a
basic need to standardise characterisation
methods for pristine nanomaterials as a
precursor to reliance on those methods for
detection in complex food or biological
matrices. The group emphasised the need to
use multiple techniques to provide a weight
of evidence for analytical conclusions. In
addition, the group highlighted the different
priorities for inorganic nanomaterials, such as
characterisation in water and characterisation
of size and morphology, and for organic
nanomaterials, such as characterisation within
matrices, including effects of coating and
matrix interactions.
The fifth group considered what types of
information would be required to make
risk management decisions. General areas
with a need to know included
composition, fate in the digestive tract, and
information on intended use relevant to
estimating population exposure.
Implementation of
recommendations
It remains to be seen if the project
outcomes serve to bolster consumer
confidence in the ability of regulators to
ensure that those nanomaterials entering
Global Business Briefing / May 2013
the food supply are safe, and that those
materials have been appropriately vetted,
based on a comprehensive consideration of
safety issues. However, the broad-based
membership of the project will hopefully
result in all participants implementing its
recommendations, due late this year.
The project’s next phase involves work
with an inter-laboratory testing group to
develop and standardise methods needed
to fill the identified information gaps. The
participants are also asking other research
teams, including some in the EU, if they
would like to collaborate in developing the
range of tools that practical regulation of
nanomaterials requires. We look forward
to seeing the product of the NanoRelease
project in enabling the sensible regulation
of nanomaterials used in food and food
contact materials.
The views expressed in contributed articles are
those of the expert authors and are not
necessarily shared by Chemical Watch.
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