Science against microbial pathogens: communicating current research and technological advances
_______________________________________________________________________________
A. Méndez-Vilas (Ed.)
Shelf life prolongation of fruit juices through essential oils and
homogenization: a review
A. Bevilacqua, M.R. Corbo, D. Campaniello, D. D'Amato, M. Gallo, B. Speranza and M. Sinigaglia
Department of Food Science, Faculty of Agricultural Science, University of Foggia, via Napoli 25, 71122 Foggia, Italy
This chapter proposes an overview of juice microbiology, then focusing on the effectiveness of essential oils and plant
extracts for the inhibition of pathogenic and spoiling microorganisms. Finally, there is a brief overview on juice
homogenization, highlighting its benefits and limits for the prolongation of juice shelf life
Keywords fruit juices; shelf life; safety; spoiling microorganisms; natural antimicrobials; alternative approaches
1. General remarks
Codex Alimentarius defines juice as “the fermentable but unfermented juice, intended for direct consumption, obtained
by the mechanical process from sound, ripe fruits, preserved exclusively by physical means. The juice must have the
characteristic colour, flavour and taste typical of the fruit from which it comes, it may be turbid or clear. The juice may
have been concentrated and later reconstituted with water suitable for the purpose of maintaining the essential
composition and quality factors of the juice. The addition of sugars or acids can be permitted but must be endorsed in
the individual standard” [1]. Juices may be prepared from nearly all fruits, if desired; the most common ones include
pineapple, orange, grapefruit, mango and passion fruit. Nevertheless, any fruits (e.g. banana, fig) can be easily pureed,
but it is more expensive to produce a clear juice from the pulp.
Generally juice is classified as puree, when the resulting consistency is a fluid that pours very slowly, or pulp when it
pours even more slowly. Juices can be concentrated for preservation, handling and storage and then reconstituted before
consumption. Nectars are made from fruit juices, to which water and sugar have been added; they contain a proscribed
minimum of juice, ranging from 25 to 50%. Table 1 reports the classification of different types of drink made from
fruits.
Flow chart for juice production is simple; a generalized scheme is reported in Appendix I.
Table 1
Designation of different kind of drinks made from fruits [2].
Type
Pure juice 100%
From concentrate
Not from concentrate
Chilled, ready to serve
Fresh squeezed
Fresh frozen
Juice blend
Puree
Nectar
Nectar base
Juice drink
Juice beverage
Juice cocktail
Fruit + ade (e.g. Lemonade)
Juice extract
Description
Pure fruit juice with nothing added, not from concentrate
Made from concentrate, reconstituted and pasteurized
Pasteurized after extraction
Made from concentrate or pasteurized juice, held refrigerated
Not pasteurized, held refrigerated
Unpasteurized, frozen after extraction
A mixture of pure juices
Pulp-containing, more viscous than juices, totally fruit
Pulpy or clear. Sugar, water and acid added, 25 to 50% juice*
Possesses sufficient flavour, acid and sugar to require water dilution for consumption*
Contains 10 to 20% juice*
Contains 10 to 20% juice*
Contains 10 to 20% juice*
Contains >10% fruit juice, sugar and water*
Fruit extracted by water, then concentrated*
*Standards for juice solids minimum varies from country to country
2. Juice microflora
Fruit juices contain water, sugars, organic acids, vitamins, and trace elements thus providing an ideal environment for
spoilage by microorganisms; on the other hand, they generally have a lower pH (pH<4.5), thus the common feature of
their potential spoilage agents is that they must be acid-loving microorganisms. The most commonly encountered
microbial genera are Acetobacter, Alicyclobacillus, Bacillus, Clostridium, Gluconobacter, Lactobacillus, Leuconostoc,
Saccharobacter, Zymomonas, and Zymobacter. However, yeasts are predominant because of their high acid tolerance
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and the ability of many of them to grow anaerobically. Pichia, Candida, Saccharomyces and Rhodotorula are the
genera mainly involved in spoiled juices; the species frequently isolated are Pichia membranifaciens, Candida maltosa,
C. sake, Saccharomyces bailii, S. bisphorus, S. cerevisiae, S. rouxii, S. bayanus, Brettanomyces intermedius,
Schizosaccharomyces pombe, Torulopsis holmii, Hanseniaspora guilliermondii, Schwanniomyces occidentalis, Dekkera
bruxellensis, Torulaspora delbruckii, Zygosaccharomyces microellipsodes, and D. naardenensis. A high level of yeast
contamination in fruit juices may be indicative of poor plant hygiene. Most spoilage yeasts are highly fermentative,
forming ethanol and CO2 from sugar, causing split cans and cartons, and explosions in glass or plastic bottles (table 2).
Amongst the spoilage yeasts, P. membranifaciens is considered as the target microorganism for the optimisation of
thermal treatments of juices because it is resistant to heat as well as to moderate amounts of salt, SO2, sorbic, benzoic
and acetic acids [3-5].
Acid-tolerant bacteria able to grow in juices include lactic acid (Lactobacillus and Leuconostoc spp.) and acetic acid
bacteria (Acetobacter and Gluconobacter spp.), Propionibacterium cyclohexanicum, Bacillus coagulans, B. megaterium,
B. macerans, B. polymyxa, B. licheniformis and B. subtilis.
Lact. plantarum var. mobilis, Lact. brevis, Leuconostoc mesenteroides and L. dextranicum are known to cause
vinegary, buttermilk off-odours and off-flavours in frozen concentrated orange juice; Bacillus species are known to
cause flat-sour type spoilage in acidic fruit beverages, because of the production of lactic acid without gas formation
(table 2). Lact. plantarum, Lact. brevis and B. coagulans are amongst the most resistant bacteria to thermal treatments
[3, 5].
In 1982, a new type of spoilage bacterium emerged in a large scale spoilage incident in Germany, during which flatsour type spoilage with offensive smelling medicinal or antiseptic characteristics was noted in commercial pasteurised
apple juice. The microbe responsible for the incident was a thermo-acidophilic, endospore-forming bacterium, later
identified as Alicyclobacillus acidoterrestris [6]. To date, 20 species and 2 subspecies that belong to this genus have
been identified and more spoilage incidents have been reported in various fruit juices, fruit juice blends, carbonated fruit
juice drinks, fruit pulps and lemonades, with apple juice as the product most often involved [7]. A. acidoterrestris is the
species primarily responsible for spoilage incidents, although other species, including A. acidiphilus, A. pomorum, A.
hesperidum, A. herbarius, A. cycloheptanicus and A. acidocaldarius have also been implicated due to their ability to
produce taint compounds [7]. Most spoilage incidents occurred in spring or summer and spoilage consisted mainly in an
off-flavour or –odour production, with or without sediment; sometimes discolouration or cloudiness occurred (table 2).
Consumer complaints were often the only reason for companies becoming aware of the problem, since the absence of
gas production made spoilage difficult to detect. The off-flavour and -odour detected have been described as medicinal,
disinfectant-like, antiseptic, phenolic, smoky and hammy and, in most cases, they have been identified as the chemical
compound guaiacol. Although guaiacol seems to be the dominant cause of taint, the halophenols 2,6-dichlorophenol
(2,6-DCP) and 2,6-dibromophenol (2,6-DBP) have been also implicated [7, 8]. Additionally, heat resistant species of
mycelial fungi such as Byssochlamys fulva, Byssochlamys nivea, Neosartorya fischeri, Talaromyces flavus,
Talaromyces macrosporus, Monascus purpureus, Paecilomyces fulvus, Aspergillus versicolor, A. restrictus, and some
species of Eupenicillium (E. brefaldianum, E. lapidosum) are reported to spoil fruit juices, pulps and concentrates. Mold
growth can result in an off-flavour or odor that may be described as “stale” or “old”, development of a mycelial mat,
reduction in sugar content, and mycotoxin production (see table 2) [3, 5].
Table 2
Microorganisms related to spoilage in fruit juices.
Microorganism
Highly fermentative yeasts
Acetobacter, Gluconobacter
Lactobacillus, Leuconostoc
Clostridium spp.
A. acidoterrestris
Bacillus spp.
Zymomonas, Saccharobacter,
Zymobacter
Heat resistant moulds
Spoilage effect
Production of ethanol and CO2 from sugars, formation of biofilm, bulging or
exploding of containers
Oxidation of ethanol, fermentation, turbidity
Sour or off-taste, buttermilk off-flavour, gummy slime or ropiness, production
of acetic acid, CO2, ethanol
Production of gas, a strong butyric odor, and increased acidity
Phenolic or antiseptic odour or off-flavour with or without light sediment or
slight haze
Flat sour
Ethanol production
Off-flavour or odour like “stale” or “old”, development of a mycelial mat,
reduction in sugar content, mycotoxin production
3. Safety of fruit juices
Numerous serious safety problems associated with fruit juices consumption are documented (table 3) [9, 10]. In the last
decade, in North America over 1700 people have fallen ill after consuming juice and cider. Most of these outbreaks
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involved unpasteurized juices such as apple, orange, lemon, pineapple, carrot, coconut, cane sugar, banana, acai and
mixed fruit juices. The most common pathogens were Escherichia coli O157:H7 and O111, Salmonella sp.,
Cryptosporidium and norovirus. A few other outbreaks were due to Vibrio cholerae, Cl. botulinum and yeasts. All
reported cases of contamination by pathogenic microorganisms were due to unpasteurized juices, and E. coli is one of
the most studied bacteria. Numerous dangerous strains of E. coli exist and are able to produce toxins of various types
and toxicities that cause different diseases. The enterohemorrhagic (EHEC) class is of most concern, due to its low
infectious dose and its association with hemorrhagic colitis (HC), hemolytic uremic syndrome (HUS), and thrombotic
thrombocytopenic purpura (TTP). In 2004 the Center for Disease Control reported an serious outbreak of 213 illnesses
associated with apple cider consumption in New York, due to Shiga toxin–producing E. coli O111 together with C.
parvum (table 3). The fresh-pressed untreated apple cider was produced at an orchard and sold directly and exclusively
to consumers [5, 9].
Salmonella infections are commonly associated with animal-derived foods, such as meat, seafood, dairy, and egg
products, rather than juices. However, outbreaks associated with fresh juice have occurred as far back as 1922. Early
outbreaks resulting in typhoid fever were associated with poor hygiene by asymptomatic Salmonella Typhi shedding
food handlers. As disinfection of water, sanitation procedures, and hygiene practices have improved, outbreaks of
typhoid fever have become far less common in developed countries. Nonetheless, given the dramatic increase of fresh
fruit imported from developing countries, typhoid fever outbreaks associated with these commodities remain a concern.
More recent outbreaks of nontyphoidal salmonellosis in fresh juice have been attributed to fecal-associated
contamination of fruit or poor processing practices. In 2005, 152 cases of Salmonella Typhimurium infection associated
with commercially distributed unpasteurized orange juice were reported (table 2). Upon inspection, Food and Drug
Administration (FDA) found that the production facility did not comply with the HACCP plan and that noncompliance
likely contributed to this outbreak [5, 9].
Cryptosporidium parvum is a highly infectious protozoan parasite causing persistent diarrhea. Common reservoirs
are ruminants including cattle and sheep. Infection with cryptosporidium does not always result in severe disease
symptoms and the organism is far more dangerous for the immunocompromised. Cryptosporidium is more commonly
associated with contaminated water; its oocysts are thick-walled, resistant to chlorine, and persistent. Presumably, the
thick wall also confers some acid resistance, as outbreaks of cryptosporidiosis have also occurred from fresh-pressed
cider. In 2003 a Cryptosporidium parvum outbreak was reported in Ohio with 144 infections associated with
commercially distributed apple cider (table 3). The cider was treated with ozone and sold directly to consumers and
businesses. Investigation deemed the ozone treatment insufficient to decrease the probability of contamination [5, 9].
In addition to pathogenic bacteria, several new pathogenic yeasts, including C. famata, C. guillermondii, C. krusei, and
C. parapsilosis can cause spoilage of fruit juices. These new pathogens are very unlikely to affect healthy individuals
but are of concern in immunocompromised patients.
Several species of molds are capable of producing different mycotoxins in fruit juices. Mycotoxins, particularly
patulin, represent a potent food safety hazard. Some molds, e.g. Penicillium expansum, P. griseofulvum, P. roqueforti
var. carneum, P. funiculosum, P. claviforme, P. granulatum, and Byssochlamys spp., produce patulin in apple juice,
while others, such as Neosartorya produce fumitremorgins, terrein, verruculogen, and fischerin. Byssochlamys species
also produce byssotoxin A and byssochlamic acid. Other mycotoxins produced in fruit juice by molds include
ochratoxin A, citrinin, and penicillic acid [3].
Viruses are not very common in fruit juices, even if a serious outbreak from the virus Hepatitis A was recorded in
2004 involving european tourists returned from Egypt (table 2).
Finally, although not implicated in foodborne outbreaks associated with fresh juices, another important pathogen is
Listeria monocytogenes because its ability to grow at conventional refrigeration temperatures and under acidic
conditions. L. monocytogenes is ubiquitous within the environment, carried by animals, and frequently found on fruits.
The minimum pH for growth of L. monocytogenes is dependant on the acidulant. For malic acid, one acid found in
juices, the lowest pH value for growth of L. monocytogenes is from 4.4 to 4.6 depending on the strain. This pathogen
causes listeriosis, a serious disease with complications including meningitis, septicemia and spontaneus abortion in
immocompromised individuals and pregnant woman [3, 5].
Table 2
Year
2000
2003
2004
2004
2005
2008
2010
Examples of fruit juice-associated outbreaks, reported by CSPI, from 2000 to 2011 [9, 10].
Microorganism
Salmonella Enteridis
Cryptosporidium parvum
Escherichia coli O111
and C. parvum
Virus Hepatitis A
Salmonella Tyhimurium
Salmonella Panama
E. coli O157:H7
N° outbreaks
143
144
213
Countries
USA
Ohio
New York
Juice type
Orange
Apple
Apple
351
152
33
7
Multiple European countries
Multiple states
Netherlands
Maryland and Pennsylvania
Orange
Orange
Orange
Apple
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4. Essential oils in juices
Consumer interest towards natural and friendly compounds caused in the past a renewed attention on alternative natural
antimicrobial from plant origin, i.e. plant extracts (essential oils, aldehydes, esters), herbs and spices. A brief focus on
these antimicrobials is reported in appendix 2.
Essential oils (EOs) are aromatic oily liquids, obtained from plant materials (flowers, buds, seeds, leaves, twig bark,
herbs, wood, fruits and roots), which can be obtained by fermentation, extraction or distillation [11, 12]. EOs are
constituted of a complex mix of various compounds, including terpenes, alcohols, chetones, phenols, acids, aldehydes,
and esters [12]; they are referred to as GRAS compounds [13], both as flavouring substances and antimicrobial hurdles
against a wide range of microorganisms, including bacteria, yeasts and moulds [14]. Many authors reported on the
effectiveness of EOs and their active compounds to inactivate and/or inhibit spoiling and pathogenic microorganisms in
juices. Their effects relies upon some main elements: the pH of the product, the kind and the concentration of EO and
the microorganism.
Concerning pH, it is generally accepted that a low pH improves the action of EOs by increasing their hydrophobicity.
Gutierrez et al. [15, 16] found that the antibacterial efficacy of oregano and thyme EOs was very high when pH was
4.33–5.32. However, this general statement was not confirmed for yeasts. Tserennadmid et al. [17] studied the antiyeast activity of some EOs (clary sage, juniper, lemon and marjoram) and used pH values ranging between 4.0 and 7.0;
they found that acididic pHs had only slight effects on the growth of yeasts. Moreover, the inhibitory effect of EOs was
maximal at pH 7 but remained good also in the acidic range, thus suggesting that the ionization form of the EO
components did not play a major role for the acidophilic yeasts.
The storage temperature is another key-factor for the antimicrobial activity of EOs. Friedman et al. [18], in fact, found
that the antimicrobial activity of some EOs towards E. coli O157:H7 and Salmonella Hadar inoculated in apple juice
was higher at 37°C than at 4 and 21°C, due probably to a higher partition coefficient of oils and to an enhanced fluidity
bacterial membrane.
Both EOs and active compounds (an active compound is the major componet of an essential oil) have been proposed
and used for juice stabilization; some examples are cinnamon, clove, lemon, lemongrass, lime and oregano oils, citrus
extract (representative of EOs) and carvacrol, cinnamaldehyde, eugenol, citral geraniol, D-limonene (representative of
active compounds of EOs) [14, 19-23].
A brief synopsis of the application of EOs in fruit juices is reported in table 4.
Table 4
Application of EOs in juices
EOs and active compounds
Oils and extracts
Cinnamon oil
Clove oil
Citrus extract
Lemon oil
Lemongrass oil
Lime oil
Oregano oil
Active compounds
Carvacrol
Cinnamaldehyde
Citral
Eugenol
Geraniol
D-limonene
Microorganisms
Spoiling bacteria
Alicyclobacillus acidoterrestris
Bacillus coagulans
Lactobacillus plantarum
Lact. brevis
Pathogens
Escherichia coli O157:H7
Listeria monocytogenes
Salmonella sp.
Yeasts
Geotrichum candidum
Pichia anomala
P. membranifaciens
Rhodotorula bacarum
Saccharomyces cerevisiae
S. bayanus
Schizosaccharomyces pombe
Moulds
Aspergillus spp.
Fusarium oxysporum
Penicillium spp.
Juice
Apple
Melon
Orange
Pear
Pineapple
Strawberry
Tomato
Watermelon
A new approach for EOs use in foods was proposed by Donsì et al. [24], who used a nano-encapsulation system (sun
flower and palm oils as organic phases; glycerol monooleate, soy lecithin, tween 20 and Cleargum(R) as emulsifying
agents) for the entrapment of a mixture of terpenes and D-limonene. They studied the antimicrobial activity of this
system towards S. cerevisiae, E. coli and Lact. delbrueckii and found a higher effect of nano-encapsulated compounds
in pear and orange juices in preserving the sensorial properties of juices.
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In general, EOs possess a strong antimicrobial activity against spoiling and pathogenic microflora of juices, being the
effect greater at low pH; however, the use of some essential oils in fruits juices is not recommended because of their
adverse effect on the sensory properties. Therefore, combinations with other preservation methods are required to
decrease their impact on food flavour [12].
5. Homogenization and combined approaches
Fruit juices, thanks to their composition, viscosity, and fluidity can be treated successfully through high pressure
homogenization (HPH). Samples of orange juice were inoculated with L. innocua ATCC 33090 at a concentration of
7.0 log cfu/ml and pressurised at 300 MPa through the primary homogenizing valve and at 30 MPa on the secondary
homogenizing valve [25]. L. innocua viable counts and injured cells were measured periodically after Ultra HPH
treatment. Cell counts decreased by approximately 2.5 log units during 18 days.
Welti-Chanes et al. [26] evaluated the effect of different HPH treatment (0-250 MPa with a maximum of five passes)
on natural microflora of orange juice and found that 5 passes at 100 MPa were required to reduce at 2.93 and 3.27 log
cfu/ml mesophilic bacteria and yeasts/moulds, respectively.
Saldo et al. [27] applied a HPH processing to apple juice and recovered that a treatment at 200 MPa reduced cell
count to the undetectable level. Maresca et al. [28] used a multi-pass HPH treatment (pressure level: 0-250 MPa;
number of passes: 1-5) for the pasteurization of orange, red orange, pineapple and Annurca apple juices, thus they found
that a 3-pass-HPH treatment at 150 MPa achieved the complete inactivation of S. cerevisiae (previously inoculated in
orange, red orange and pineapple juices) as well as the stabilization of endogenous microflora of fresh Annurca apple
juice. Patrignani et al. [29, 30] studied the potentialities of HPH (100 MPa for 1-8 passes) to inactivate S. cerevisiae
635 and Zygosaccharomyces bailii, in apricot and carrot juices. Initial inoculum levels of S. cerevisiae were about 3 and
6 log cfu/ml, whereas initial inoculum level of Z. bailii was 5 log cfu/g. They confirmed the significance of the number
of passes, pressure level and food matrix on the effectiveness of HPH.
HPH treatment was considered a good option for non thermal production of Annurca apple juice by Donsì et al. [31],
Who applied homogenization at different pressure levels (150-300 MPa) for the inactivation of endogenous
microflora; thus the shelf life of clear juice and juice with pulp could be prolonged for many weeks upon HPH
treatment at 250 and 300 MPa.
Table 4 proposes a summary of HPH use in juices.
Table 4 Application of HPH in juices
Juice
Apple
Carrot
Mango
Pinepple
Orange
Tomato
Targets
Alicyclobacillus acidoterrestris
Escherichia coli O157.H7
Listeria monocytogenes
Lactic acid bacteria
Saccharomyces cerevisiae
Emericella nidulans
Fusarium oxysporum
Penicillium expansum
Aspergillus niger
Talaromyces macrosporus
Effect on juice characteristics
Stabilization of cloudy appearance
No effect on pH, color, content of
vitamin C and phenols
Inhibiton of enzymatic activities
In order to reduce the negative effect on HPH and EOs on food quality, the application of combined hurdles was
studied. Hurdle technology is based on the concept of applying a combination of some mild treatments to gradually
reduce or inhibit microbial counts, with a better retention of sensory properties and nutritive value than those obtained
using only a single process [32] Concerning the combined application of HPH with other treatments, some examples are
the papers of Pathanibul et al. [33], Kumar et al. [34], Tribst et al. [35] and Bevilacqua et al. [36].
Pathanibul et al. [33] homogenized apple and carrot juices with high pressure in a range from 0 to 350 MPa in
combination with nisin (10 IU/ml) to inactivate E. coli and L. innocua (ca. 7 log cfu/ml); E. coli seemed more sensitive
than L. innocua, as a reduction of 5 log cfu/ml was achieved at pressures > 250 MPa. E. coli was also inactivated in
apple juice and cider using a combination of seven levels of pressures (from 50 to 350 MPa) and two type of chitosan,
regular and water soluble, (0.01 and 0.1%) by Kumar et al. [34]. In particular, HPH induced significant inactivation in
the range of 100 to 200 MPa; when HPH treatment was combined with incremental quantities of chitosan (both types),
a synergistic effect was observed. These results were more evident in apple juice than apple cider at same homogenizing
pressures.
Tribst et al. [35] applied HPH and thermal treatment on A. niger conidia inoculated in mango nectar and they
concluded that 5.03 minutes of thermal treatment and 300 MPa reduced mould by 5 log cfu/ml, with a synergistic
effect. Finally, Bevilacqua et al. [36] studied the combination of citrus extract (0-3 ppm), benzoate (0-300 ppm) and
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homogenization (0-90 MPa) for the inhibition of Pichia membranifaciens; the centroid approach was used to combine
the three variables and point out their individual and interactive effects. Thus they found that citrus extract could be a
suitable alternative for the inhibition of P. membranifaciens in acidic drinks, as a low amount of this compound (3 ppm)
increased the lag phase by 60–70%. In addition, homogenization (90 MPa) was able to reduce significantly the initial
cell number.
6. Conclusions and future perspectives
The use of alternative approaches for juice stabilization appears as a promising trend, due to the increased awareness of
consumers towards natural, fresh and nutrient-enriched foods. Juices are usually referred as “vitamin containing foods”;
therefore, the use of a processing able to retain vitamins and nutrients or minimize their loss could be advisable.
However, some issues related to EOs and homogenization should be solved, i.e.:
1.The organoleptic impact of EOs. It would be advisable the use of extracts and/or oils water-soluble, odourless
and colourless.
2.The optimization of homogenization and/or combined approaches, in order to make possible a real industrial
production (costs, volumes, shelf life duration).
Briefly, why and how use EOs and HPH in juices? Figure 1 could be a possible answer.
PROCESSING
GREEN CONSUMERISM
Reduce initial contamination
Thermal treat.
HPH
Retain or minimize the loss of nutrients.
Use friendly compounds
EOs
Thermal treat.
HPH
EOs
Control post-processing contamination
Thermal treat.
HPH
EOs
SOLUTION. Use a combined approach (HPH+EOs) to:
Reduce the initial contamination
Control post-processing contamination
Retain sensorial and nutritional quality
Figure 1. Why use Essential oils and homogenization in juices? A possible answer. (EOs, essential oils; HPH, homogenization;
thermal treat., thermal treatment).
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References
[1] FAO. Fruit Juices and Related Products. Codex Alimentarius. Volume 6; 1992.
[2] Bates RP, Morris JR, Crandall PG. Principles and practices of small-and medim –scale fruit juice processing. FAO
Agricultural Services Bulletin. 2001.
[3] Vasavada PC. Microbiology of fruit juice and beverages. In: Foster T, Vasavada CP, eds. Beverage quality and safety. Boca
Raton, FL: CRC Press; 2003.
[4] Boekhout T, Robert V. Yeasts in food. Beneficial and detrimental aspects. Hamburg: Behr’s Verlag; 2003.
[5] Keller SE, Miller AJ. Microbiological safety of fresh citrus and apple juices. In: Sapers GM, Gorny JR, Yousef AE, eds.
Microbiology of fruit and vegetables. Boca Raton, FL: CRC Press Taylor and Francis Group, 2006:211-224.
[6] Cerny G, Hennlich W, Poralla K. Fruchtsaftverderb durch Bacillen: Isolierung und Charakterisierung des Verderbserregers.
Zeitschrift für Lebensmittel Untersuchung und Forschung. 1984:179-224.
[7] Steyn CE, Cameron M, Witthuhn RC. Occurrence of Alicyclobacillus in the fruit processing environment — A review.
International Journal of Food Microbiology. 2011; 147:1–11.
[8] Parish ME. Spoilage of juices and beverages by Alicyclobacillus spp. In: Sapers GM, Gorny JR, Yousef AE, eds.
Microbiology of fruit and vegetables. Boca Raton, FL: CRC Press Taylor and Francis Group, 2006:159-180.
[9] Vojdani JD, Beuchat LR, Tauxe RV. Juice-associated outbreaks of human illness in the United States, 1995 through 2005.
Journal of Food Protection. 2008; 71:356–364.
[10] Center
for
Science
in
the
Public
Interest,
CSPI.
Outbreaks
and
Recalls.
Available
at
http://www.cspinet.org/foodsafety/outbreak_report.html. Accessed May 5, 2011.
[11] Burt S. Essential oils and their antibacterial properties and potential applications in foods-a review. International Journal of
Food Microbiology. 2004; 94:223-253.
[12] Raybaudi-Massilia RM, Mosqueda-Melgar J, Soliva-Fortuny R, Martìn-Belloso O. Control of pathogenic and spoilage
microorganisms in fresh-cut fruits and fruit juices by traditional and alternative natural antimicrobials. Comprehensive
reviews in food science and food safety. 2009; 8:157-180.
[13] U.S.
Food
and
Drug
Administration
(USFDA).
Food
additive
status
list.
Available
at
http://www.cfsan.fda.goc/dms/rdb/opa-appa.html. Accessed May 5, 2011.
[14] Speranza B, Corbo MR. Essential oils for preserving perishable foods: possibilities and limitations. In. Bevilacqua A,
Corbo MR, Sinigaglia M, eds. Application of alternative food-preservation technologies to enhance food-safety and
stability. Sharjah UAE: Bentham Publisher, 2010:35-57.
[15] Gutierrez J, Barry-Ryan C, Bourke P. The antimicrobial efficacy of plant essential oil combinations and interactions with
food ingredients. International Journal of Food Microbiology. 2008; 124:91-97.
[16] Gutierrez J, Barry-Ryan C, Bourke P. Antimicrobial activity of plant essential oils using food model media: efficacy,
synergistic potential and interactions with food components. Food Microbiology. 2009; 26:142-150.
[17] Tserennadmid R, Takò M, Galgòczy L, Pesti M, Vagvölgyi C, Almàssy K, Krisch J. Anti yeast activities of some esential
oils in growth medium, fruit juices and milk. International Journal of Food Microbiology. 2011; 144:480-486.
[18] Friedman M, Henika PR, Levin CE, Mandrell RE. Antibacterial activities of plant essential oils and their components
against Escherichia coli O157:H7 and Salmonella enterica in apple juice. Journal of Agricultural and Food Chemistry.
2004; 52:6042-6048.
[19] Fisher K, Phillips C. Potential uses of essential oils in food; is citrus the answer. Trends in Food Science and Technology.
2008; 19:156-164.
[20] Bevilacqua A, Corbo MR, Sinigaglia M. In vitro evaluation of the antimicrobial activity of eugenol, limonene and citrus
extract against bacteria and yeasts, representative of the spoiling microflora of fruit juices. Journal of Food Protection.
2010; 73:888-894.
[21] Bevilacqua A, Corbo MR, Sinigaglia M. Combining eugenol and cinnamaldehyde to control the growth of Alicyclobacillus
acidoterrestris. Food Control. 2010; 21:172-177.
[22] Bevilacqua A, Sinigaglia M, Corbo MR. Use of the surface response methodology and desirability approach to model
Alicyclobacillus acidoterrestris spore inactivation. International Journal of Food Science and Technology. 2010; 45:12191227.
[23] Campaniello D, Corbo MR, Sinigaglia M. Antifungal activity of eugenol against Penicillium, Aspergillus and Fusarium
species. Journal of Food Protection. 2010; 73:1124-1128.
[24] Donsì F, Annunziata M, Sessa M, Ferrari G. Nanoencapsulation of essential oils to enhance their antimicrobial activity.
LWT-Food Science and Technology. 2011; doi:10.1016/j.lwt.2011.03.003.
[25] Briñez WJ, Roig-Sagués, AX, Hernández Herrero MM, Guamis López B. Inactivation of Listeria innocua in milk and
orange juice by ultra high-pressure homogenization. Journal of Food Protection. 2006; 69:86–92.
[26] Welti-Chanes J, Ochoa-Velasco CE, Guerrero-Beltran JA. High-pressure homogenization of orange juice to inactivate
pectinmethylesterase. Innovative Food Science and Emerging Technologies. 2009; 10:457-462.
[27] Saldo J, Suarez-Jacobo A, Gervilla R, Guamis B, Roig-Saguez AX. Use of ultra-high-pressure homogenization to preserve
apple juice without heat damage. International Journal of High Pressure Research. 2009; 29:52-56.
[28] Maresca P, Donsì F, Ferrari G. Application of a multi-pass high-pressure homogenization treatment for the pasteurization
of fruit juices. Journal of Food Engineering. 2011; 104: 364-372.
[29] Patrignani F, Vannini L, Kamdem SLS, Lanciotti R, Guerzoni ME. Effect of high pressure homogenization on
Saccharomyces cerevisiae inactivation and physico-chemical features in apricot and carrot juices. International Journal of
Food Microbiology. 2009; 136:26-31.
[30] Patrignani F, Vannini L, Kamdem SLS, Lanciotti R, Guerzoni ME. Potentialities of high-pressure homogenization to
inactivate Zygosaccharomyces bailii in fruit juices. Journal of Food Science. 2010; 75:M116-M120.
©FORMATEX 2011
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______________________________________________________________________________
A. Méndez-Vilas (Ed.)
[31] Donsì F, Esposito L, Lenza E, Senatore B, Ferrari G. Production of shelf stable Annurca apple juice with pulp by high
pressure homogenization. International Journal of Food Engineering. 2009; 5:article 12.
[32] Leistner L. Principles and applications of hurdle technology. In: Gould GW, ed. New methods of food preservation.
London: Blackie Academic and Professional, 1994:1-21.
[33] Pathanibul P, Taylor TM, Davidson PM, Harte F. Inactivation of Escherichia coli and Listeria innocua in apple and carrot
juices using high pressure homogenization and nisin. International Journal of Food Microbiology. 2009; 129:316-320.
[34] Kumar S, Thippareddi H, Subbiah J, Zivanovic S, Davidson PM, Harte F. Inactivation of Escherichia coli K-12 in apple
juice using combination of high-pressure homogenization and chitosan. Journal of Food Science. 2009; 78:M8-M14.
[35] Tribst AAL, Franchi MA, de Massaguer PR, Cristianini M. Quality of mango nectar processed by high-pressure
homogenization with optimized heat treatment. Journal of Food Science. 2011; 76:M106-M110.
[36] Bevilacqua A, Corbo MR, Sinigaglia M. Inhibition of Pichia membranifaciens by homogenization and antimicrobials.
Food and Bioprocess Technology. 2010; doi: 10.1007/s11947-010-0450-1.
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The selected fruits are washed in a trough using potable water.
Inspection can be manual, contingent upon workers observing and
removing defects or automatic, effected by computer controlled sensors
to detect off colour, shape or size.
This stage is necessary for some type of fruit (e.g. pineapple). The fruits
are peeled, cored and deseed manually or with automatic machine,
depending on the scale of operation.
Necessary to remove stones, leaves and soil.
Inspection and removal of unsound fruit is very important,
because after juicing one piece of defective fruit can end up
contaminating an entire lot of juice.
Necessary to peel the fruit and remove stones or seeds. If
necessary, chop the fruit into pieces that will fit into the
liquidiser or pulper.
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Cool, label and store
Check the label and storage conditions are correct.
The correct weight should be filled into the packages each
time.
The pasteurized juice is allowed to cool and then arranged in corrugated
cartons and sealed.
Tetra brick packages can also be used. The products should be hot-filled
into clean, sterilized bottles.
If Tetra brick is to be used for packaging the juice, bulk pasteurization
would be done before the packaging.
Alternatively, the bottled juice is pasteurized at a predetermined
temperature and time using a pasteurizer.
It is necessary to destroy enzymes and microorganisms. The
temperature and time of heating are critical for achieving both
the correct shelf life of the drink and retaining a good colour
and flavour.
Fill and seal
Hot filling into
bottles
The mixed juice is bottled and corked, either manually or with
automatic bottle filling machine, depending on the scale of operation.
Check fill-weight and correctly sealed pack.
Deaeration
Heat
Deaeration can be accomplished by either flashing the heated juice into
a vacuum chamber or saturating the juice with an inert gas. Nitrogen or
carbon dioxide is bubbled through the juice prior to storing under an
inert atmosphere.
Check the levels of dissolved oxygen. Clearly, once air is
removed or replaced by inert gas, the juice must be protected
from the atmosphere in all subsequent processing steps.
It is essential to work quickly between the extraction of the There are several methods to extract juice depending on the type of fruit
juice and the bottling stage. Extracted fruit juice that is left to you use. Apples are pressed, whereas melon and papaya are steamed to
stand in the heat will start to ferment and may start to
release the juice. Pulper is used for pineapples, mango, strawberry and
discolour due to enzyme activity.
other fleshing fruits.
Select mature, undamaged fruits. Any fruits that are mouldy or underripe should be sorted and removed.
Check for full maturity.
Rapid methods such as centrifugation and filtration can produce a clear
juice. Juices where a cloud is desired generally do not require filtration;
centrifugation is adequate. Sometimes may be necessary to use pectic
enzymes to break down the pectin and to help clear the juice.
Heat
Cut/slice/core
Methods
Quality Assurance
Check the production of a clear or brilliantly clear juice and
the prevention of post filtration turbidity.
Filter/clarification
of juice
Juice extraction
Sort / grade
Wash
Harvest fruit
Stage in process
APPENDIX 1 Juice production
Science against microbial pathogens: communicating current research and technological advances
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A. Méndez-Vilas (Ed.)
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APPENDIX 2 Alternative natural antimicrobials from plant origin
Antimicrobials
Essential oils (EOs)
Active compounds
Aldehydes and esters
Herbs and spices
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Definition/details
Aromatic oily liquids obtained from plant material by fermentation,
extraction or distillation. They are a mixture of many compounds, some
of them labelled as "major component", the other present as traces.
The majority of EOs are regarded as GRAS component
Major component of EOS; some examples are eugenol,
cinnamaldehyde, thymol, carvacrol, menthol. Generally, they possess a
phenolic structure.
Aldehydes are dominant compounds released by plant tissue through
the lipoxygenase pathway after some damage. Some examples of
aldehydes showing an antimicrobial effect are hexenal, trans-2-hexenal
and hexyl-acetate.
Vanillin is included in aldehyde groups; although it is regarded as
GRAS compound, its use as antimicrobial in juice is limited by the fact
that some microorganisms, like A. acidoterrestris, are able to catabolize
vanillin for the production of guaiacol (responsible of a severe offflavour in juices).
There are few data on the use of herbs and spice in juices as
antimicrobial compounds; some example are mint and cinnamon
powder.
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