Nitrates carcinogen cured meats

Although the potentially carcinogenic nitrosamines may he present in foods, particularly cured meats, occurrence is infrequent and at low levels. USDA regulations stipulate that ascorbic acid be added to cured meats at live limes the level of nitrates and nitrites to prevent the formation of carcinogenic Af-nitroso compounds. See also Food Additives. 

A number of nitroso compounds, A-nitrosamines among them, are potent carcinogens. The most common carcinogenic nitrosamines, found mainly in protein food, are A-nitroso-dimethylamine (NDMA), A-nitroso-diethylamine (NDEA), A-nitroso-pyrrolidine (N-Pyr), and A-nitroso-piperidine (N-Pip). These compounds supposedly increase the risk of colon, rectum, stomach, pancreas, and bladder cancers. Nitrosamines are most prevalent in cured meats, but have also been detected in smoked fish, soy protein foods dried by direct flame, and food-contact elastic nettings. Dietary surveys indicated weekly mean intakes of these compounds amounting to about 3 pg per person (Anon., 1988 Cassens, 1995). In addition, the precursors of nitrosamines, especially nitrate, are abundant in some leafy and root vegetables (Table 14.1). 

Nitrates and nitrites are spread within environmental, food, industrial, and physiological systems. Nitrate may be reduced by bacteria to nitrite, and nitrite produces carcinogenic nitrosamines. Nitrite is also commonly employed in cured meat products to provide antimicrobial action, color fixation, and preservation. Nitrite can oxidize hemoglobin iron(II) to iron(III) resulting in methemoglobin, leading to a condition known as methemoglobinemia in children mainly. In excess, nitrates and nitrites may be toxic. 

N-Ethyl-N-nitrosourea is one of the most potent carcinogens known/ These compoimds, as well as diazomethane and other related substances, probably act via a common intermediate CH3N2 or C2H5N2. Any secondary amine will react with nitrous acid to form a nifrosamine (Eq. 27-25). Terhary amines can also read wifh loss of one alkyl group. This can occur in the stomach, and the nitrosamines may be absorbed into the system. All plants contain some nitrate and some, such as spinach and beets, have large amounts. Bacon and other cured R R meats contain both nitrites and nitrates, and many drugs and natural food... 

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