Nitrite, nitrosamines, and cancer.

Carcinogenic N-nitroso compounds are formed from the reaction of naturally-occurring amines and nitrites that may be added to foods or produced by bacterial reduction of nitrate. N-Nitroso compounds can be produced during processing, storage and preparation of foods and in the mammalian stomach. Factors that influence the rates of nitrosation reactions include pH, temperature, catalysts, and inhibitors. Predictions of the extent of nitrosation are complicated by these factors and ultimately the amounts and types of N-nitroso compounds present must be determined by direct analysis. Methods for detection and estimation of volatile nitrosamines are available and low levels (parts per billion) have been found in some cured meat and fish products. General methods for detection of all N-nitroso compounds are not available yet, but are under development. Evaluation of the risk to human populations from these compounds is difficult in the absence of more comprehensive data on their environmental distribution.