BLBS102-c43 BLBS102-Simpson March 21, 2012 14:30 Trim: 276mm X 219mm Printer Name: Yet to Come
826 Part 8: Food Safety and Food Allergenssafe for human consumption, if they are handled and stored
properly.Vegetable ProductsVegetables may also be fermented to preserve them or form mod-
ified products with characteristic flavors and textures. Fermented
vegetable products include pickles, ripe olives, sauerkraut, doen-
jang, shoyu, stinky tofu, miso, tempeh, injera, kimchi, koji, natto,
soy sauce, brandy, cider, sake, and vinegar; they are produced
from sources such as beans, grains, cucumbers, lettuce, olives,
cabbage, turnips, fruits, and rice. In general, biogenic amine
content is very low in fresh vegetables; however, the concentra-
tion increases during the fermentations process and throughout
storage. Sauerkraut is made from shredded cabbage by fermenta-
tion with lactic acid bacteria. In the case of fermented vegetable
products, there does not appear to be a significant correlation
between biogenic amine levels and spoilage unlike the situation
with fermented meat products, and compounds like tyramine,
putrescine, and cadaverine are commonly found in fermented
vegetable products (Potter and Hotchkiss 1998, Kalac et al. 1999,
2000a, 2000b).
The amounts of biogenic amines present in fermented veg-
etable products also vary and depend on factors such as temper-
ature, salt content, and pH/acidity, as well as starter culture type.
These factors all affect the growth and metabolism of the organ-
ism, which influence the formation of the biogenic amines. Low
temperatures generally minimize microbial growth and prolifer-
ation, and enzyme activities to reduce biogenic amine formation,
while elevated temperatures tend to do the reverse.
Salt plays an important role in the fermentation of vegetables.
By modulating theAwlevels, salting can influence the texture
of fermented vegetable products. For example, under dry salted
fermentation conditions, product firmness is enhanced with in-
creasing salt content. Although a high salt may suppress the
activity of certain (desirable) bacteria, there are halophilic bac-
teria that are salt tolerant, and advantage may be taken of this
fact to use halophilic bacteria such asEnterococcito overcome
the growth and proliferation of a moderately salt tolerantLac-
tobacillispecies in fermented vegetable products (Kalac et al.
1999).
Acidity and pH are also important in the fermentation of veg-
etables. Hitherto, the use of starter cultures helps to exclude
undesirable microorganisms by generating an acidic milieu that
is not conducive for the growth of certain microorganisms. Thus,
the pH level in a product can determine the types of microorgan-
isms that would be dominant in the course of the fermentation
process. For instance,LactobacillusandStreptococcusspecies
are acid tolerant, and when they are used in mixed cultures,
species likeLeuconostoc mesenteroideswould initiate the pro-
cess and produce an acidic environment, and then be replaced
byL. plantarumtill the lactic acid level rises sufficiently to kill
theL. plantarumand be replaced byL. pentoaceticus.L. plan-
tarumis a typical tyramine producer; thus, products formed with
such cultures would be expected to accumulate biogenic amines
(Battcock and Azam-Ali 1998, Suzzi and Gardini 2003).Fermented vegetable products also accumulate biogenic
amines during storage. For example, the levels of tyramine and
putrescine in sauerkraut increase during storage, and the longer
the storage period, the more of these biogenic amines accumu-
late (Kalac et al. 2000a, 2000b).Non-fermented FoodsBiogenic amines occur in non-fermented foods also. Fresh fish
and meats in particular are known to contain biogenic amines
due to their high protein and free amino acid contents and their
high perishability. These food products have also been associ-
ated with histamine poisoning, which also attests to the presence
of these compounds. Biogenic amines in non-fermented foods
are also formed by the action of decarboxylating and proteolytic
enzymes exuded by microorganisms naturally present as part of
the native microbial flora of fish and meats, or microorganisms
purposefully added as starter culture, or added through contam-
ination. High levels of biogenic amines in foodstuffs may be
used as indices of undesirable microbial growth and spoilage.FishBiogenic amines in fish are of particular health concern because
they cause histamine poisoning in humans (Sanchez-Guerrero
et al. 1997). Histamine poisoning or scombroid fish poison-
ing (scombrotoxicosis) is the most widespread form of seafood
poisoning in fish-producing and fish-consuming communities.
Fish in theScombridaeandScomberesocidaefamilies as well
as non-scombroid fish have both been implicated in biogenic
amine poisoning of humans. These include fish species like blue-
fish (Pomatomusspp.), bonito (Sardaspp.), mackerel (Scomber
spp.), mahi mahi (Coryphaenaspp.), marlin (Makairaspp.),
pilchards (Sardina pilchardus), sardines (Sardinellaspp.), saury
(Cololabis saida), sockeye salmon (Oncorhynchus nerka), tuna
(Thunnusspp.), and yellowtail (Seriola lalandii) (Lehane and
Olley 2000, Sarkadi 2009). These fish species tend to have high
levels of free histidine in their tissues, which may undergo de-
carboxylation to form the toxic histamine. The levels of biogenic
amines in fish tissues vary greatly and are influenced by various
factors including muscle type, the native microflora, harvest-
ing, and postharvest management practices (including handling,
processing, transportation and storage; Veciana-Nogues et al.
1997a, 1997b, Gloria et al. 1999).
Of the biogenic amines found in fish tissues, histamine usu-
ally tends to be the most abundant, followed by putrescine and
cadaverine in that order. For example, tuna fish samples stored at
20 ◦C produced histamine, cadaverine, and putrescine levels of
3103 μg/g, 44.2μg/g, and 3.0μg/g, respectively, after 48 hours
of storage (Veciana-Nogues et al. 1997a, 1997b). Nonetheless,
these biogenic amines may not occur in all fish tissues, as is the
case for tyramine, which is absent in sea bream (Sparus aurata)
but present in anchovies (Engraulis mordax; Koutsoumanis et al.
1999).
The relative amounts of biogenic amines and their distribution
in fish tissues depend to a large extent on the types of microor-
ganisms associated with the raw material and their capacity to