Food Biochemistry and Food Processing (2 edition)

BLBS102-c43 BLBS102-Simpson March 21, 2012 14:30 Trim: 276mm X 219mm Printer Name: Yet to Come

824 Part 8: Food Safety and Food Allergens

act on theα-carboxyl group of the appropriatel-amino acid to

produce the corresponding biogenic amine and carbon dioxide.

The enzymatic decarboxylation process depends on various fac-

tors such as the availability of the substrate in free form, the

presence of decarboxylase-producing microorganisms, and the

reaction medium conditions. The amino acid substrates for the

decarboxylations are either naturally present in the food mate-

rial or produced via proteolysis by endogenous proteases in the

raw material. Also, decarboxylase enzyme-producing microor-

ganisms may be present as part of the natural micro flora of a

food product, and they may be introduced by contamination or

added as part of a starter culture. Medium conditions that favor

the growth of the bacteria (i.e., carbon source, pH, temperature,

availability of O 2 , and light) and production of the decarboxylase

enzymes in active forms all promote the formation of biogenic

amines.

Biogenic amines may also be broken down by the MAO en-

zyme system to control the levels of these compounds. Prote-

olysis to form free amino acids may also be potentiated by the

action of exogenous proteases that are intentionally added for

the modification of foodstuffs.

In foods and the food industry, it is the exogenously formed

biogenic amines that are of particular interest. Heterocyclic

amines (HCAs) are formed in muscle foods (beef, pork, poul-

try, and fish) during high temperature cooking procedures such

as frying, broiling, and barbecuing. The amino acids from food

proteins (meats) condense with creatinine to result in the HCAs.

HCAs can be potent mutagens and carcinogens and may increase

the risk of cancer for humans (Adamson and Thorgeirsson 1995).

Nonetheless, biogenic amines are also used to treat depression

and to promote positive mood.

OCCURRENCE IN FOOD PRODUCTS

Fermented Food Sources

Fermentation is a biological method of processing foodstuff

to preserve its quality or to transform foods into stable and

useful forms. The fermentation process invariably makes fin-

ished products with characteristic flavors and textural proper-

ties. The process is potentiated mostly by microbial activity and

metabolism and by enzymes. Several different microorganisms

includingLactococcus, Lactobacillus, Leuconostoc, Streptococ-

cus,andPediococcusspecies have been shown to participate in

various food fermentations. These microorganisms may be nat-

urally present in the food material or added to foods as starter

culture, and they secrete their enzymes (including various decar-

boxylases and hydrolases) in foods for their transformation. As

a result, certain fermented foods may accumulate large amounts

of biogenic amines through the decarboxylation of amino acids

by microbial decarboxylases or via proteolysis by proteases to

generate intermediates (free amino acids) that may condense

with creatinine to form heterocyclic biogenic amines. For ex-

ample, products such as the Chinese mitten crab, beer, cheese,

and other fermented foods have all been shown to accumulate

high levels of histamine during storage (Stratton et al. 1991,

Izquierdo-Pulido et al. 1999, Xu et al. 2009). Although the pres-

ence of biogenic amines may not always indicate spoilage, their

presence in food products is not desired due to their potential

health effects.

Cheese

Cheese is a commonly consumed fermented food product. Dur-

ing fermentation and ripening of cheeses, milk casein is hy-

drolyzed by proteases and peptidases into a mixture of smaller

peptides and free amino acids. Some of the free amino acids pro-

duced become substrates for the decarboxylases of microorgan-

isms associated with cheeses to form biogenic amines (mainly,

putrescine, cadaverine, histamine, and tyramine) in the products

(ten Brink et al. 1990). As well, free amino acids from proteol-

ysis may form heterocyclic biogenic amines with creatinine.

Some microorganisms have been implicated in the formation

of histamine, tyramine, putrescine, and cadaverine in cheeses.

For example,Lactobacillus buchneriis known to produce vast

amounts of histamine in cheeses, which can potentially elicit

histamine poisoning in consumers, whileL. brevisandEntero-

coccus faecalishave also been implicated in the formation of

tyramine in certain cheese products (Stratton et al. 1991, Shalaby

1996).

Certain conditions can promote or inhibit the formation of

biogenic amines in foods by microbial enzymes. The increase

of free amino acids during fermentation is one of the main pro-

moters of biogenic amines formation since the amino acids are

the substrates for the enzymatic decarboxylase action, leading

to the formation of the amines and carbon dioxide. As a re-

sult, cheeses with longer ripening times and higher degrees of

proteolysis may have higher amounts of biogenic amines. The

use of high temperatures during cheese making and/or storage

may also increase biogenic amine levels in the products. When

cheeses are stored or transported under different temperature

conditions, the products handled under proper refrigeration con-

ditions (4◦C) tend to have lower levels of biogenic amines than

their counterparts stored or transported at elevated temperatures

(e.g., 25◦C; Shalaby 1996, Pinho et al. 2001). On the other

hand, high-temperature pasteurization of milk prior to its use

for cheese-making can curtail biogenic amine formation in the

product, and when high-temperature pasteurized milk is used in

combination with particular starter cultures, it could result in the

formation of considerably lower levels of biogenic amines in the

cheese product; the use of appropriate levels of acid and salt may

also slow down biogenic amine production in cheese products

(Ordo ́nez et al. 1997, Valsamaki et al. 2000, Martuscelli et al. ̃

2009).

Alcoholic Beverages

Alcoholic beverages, including beer and wines, are produced

from plant materials by microbial fermentation process (e.g.,

red wine is produced by fermentation of grape must) and are

common sources of biogenic amines. Beer and red wines have

been implicated in outbreaks of histamine and tyramine poi-

soning. Biogenic amines in alcohol act synergistically to elicit

various adverse health symptoms such as nausea, respiratory