Formation of volatile N-nitrosamines from food products, especially fish, under simulated gastric conditions.

Most food products do not form volatile nitrosamines under the simulated gastric conditions employed in the present study. Fish and other seafood products, however, regularly form nitrosodimethylamine (NDMA), sometimes in amounts of tens of micrograms per 'portion'. These results corroborate the tentative conclusions of a previous report from this laboratory. An attempt has been made to assess the influences of fish species, method of processing (freezing, smoking, canning, marinating, boiling, frying) and degree of freshness, but no particular type of product can be singled out as being a regular source of exceptional NDMA formation. If the model system employed is a valid approximation to the conditions obtaining in the human stomach, these studies suggest that the amounts of NDMA formed in vivo from certain fish samples might far exceed those already present in food products before consumption.