Sources of N-nitrosamine contamination in foods.

It has been well established that human foods may contain trace amounts of carcinogenic N-nitrosamines. Originally, it was thought that the use of nitrite as a curing agent for flesh foods was the major source of these trace compounds in the diet. Subsequent research has clearly shown that other processing and packaging procedures can also introduce trace amounts of these carcinogens into foods. These procedures include drying foods in direct flame heated air, migration from food contact surfaces and direct addition as contaminants. In addition, other reports of N-nitrosamines in foods have less well defined routes of contamination. These sources of N-nitrosamines in foods will each be briefly reviewed in this paper and recent data from our laboratory concerning N-nitrosamines in products which directly contact foods presented. We also are reporting the N-nitrosothiazolidine content of fried-out bacon fat.