Foodborne Chemicals: Antibiotics, Heterocyclic Amines, and Nitrates

Antibiotics

Untreated pharmaceutical drugs may pass easily into soil and water supplies once released into the environment. Public health authorities are concerned that antibiotic use on farms may result in antibiotic resistance. In a study done in Oklahoma, bacterial samples from turkey, cattle, and chicken farms and from retail meat samples were shown to be resistant to several antibiotics and to be capable of transferring resistance to other bacterial species. Some experts have suggested that the development of resistance in humans may be due, in some cases, to antibiotic–resistant bacteria of farm animals that contaminate products entering the human food supply.

Heterocyclic Amines

Heterocyclic amines (HCAs) are carcinogenic compounds that form during cooking of all meats, including fish. In general, grilling causes the greatest amount of HCA formation, followed by pan–frying, because of the long cooking times and high cooking temperatures. Chicken products contribute the greatest quantity of HCAs in North American diets, compared with other meats, in part due to the large quantity of chicken products consumed.

Several cancers are associated with HCAs, including cancers of the colon, rectum, stomach, breast, lung, and prostate. Modification of cooking methods (such as microwaving) and reducing or avoiding meat consumption are effective steps to prevent formation of HCAs.

The intake of cruciferous vegetables, such as broccoli and Brussels sprouts, may decrease HCAs in the body by causing the liver to more quickly eliminate them.

Nitrates

Nitrates and nitrites are used as preservatives in hot dogs, pickled meats, some cheeses, and other foods. They are metabolized in the body to form compounds that are associated with gastric cancer.

Nitrates are also a natural component of many vegetables, and produce commonly contains nitrate residues from fertilizers. However, despite the presence of nitrates in and on many fruits and vegetables, protection from gastric cancer is afforded by the consumption of these foods, presumably because of the vitamins and minerals in these foods. Other foods and nutrients that affect nitrate metabolism include fruits and vegetables, garlic and other allium species, vitamin E, and selenium.