SCREENING OF HEAT-PROCESSED FINNISH FOODS FOR THE MUTAGENS 2-AMINO-3,8-DIMETHYLIMIDAZO[4,5-F]QUINOXALINE, 2-AMINO-3,4,8-TRIMETHYLIMIDAZO[4,5-F]QUINOXALINE AND 2-AMINO-1-METHYL-6-PHENYLIMIDAZO[4,5-B]PYRIDINE

The concentrations of 2-amino-3,8-dimethylimidazo[4,5-f]quinoxaline (M eIQx), 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP) and DiMe IQx (i.e. the sum of 2-amino-3,4,8-trimethylimidazo[4,5-f]quinoxaline and 2-amino-3,7,8-trimethylimidazo[4,5-f]quinoxaline) were determined as their 3,5-bis(trifluoromethyl)benzyl bromide derivatives in commerc ial heat-processed daily Finnish foods using the gas chromatography-ma ss spectrometry technique with negative chemical ionization. With this technique it was possible to detect picogram quantities of halogenate d aminoimidazoaarene (AIA) derivatives. The mutagenic activities of th e food samples were tested using the Ames Salmonella assay. The mutage nicities and amounts of the AIA compounds analysed varied considerably in the food samples. All the flame-broiled fish samples and the major ity of the grilled pork and chicken samples were positive in the test; of all the food samples tested fish samples had the highest mutagenic activity. Industrially produced meat patties were non-mutagenic. The amounts of MeIQx, DiMeIQx and PhIP in grilled products that exhibited mutagenic activity varied in the range 0.04 to 0.4, 0.03 to 0.2 and 0. 5 to 3.8 ng per g cooked food, respectively. Some of the highly mutage nic flame-broiled fish samples contained only PhIP, the amount of whic h varied from 0.5 to 5.5 ng per g fish. One of the samples also contai ned a small amount of MeIQx. None of the non-mutagenic meat patties co ntained detectable amounts of MeIQx, DiMeIQx or PhIP. In this screenin g study evaluation of the occurrence of AIA compounds was carried out in a relatively wide range of commercial heat-processed Finnish foods. Considerable differences between equivalent products from different m anufacturers were found in many cases. This variation indicates that i ndustrial processing of food has a marked effect on the mutagenic acti vity of the product.