[Improved microbiological assay of heterocyclic aromatic amines in cooked food]

Heating of protein, especially muscle meat and meat extracts, can result in the formation of heterocyclic aromatic amines (HA) which are carcinogenic in animals. They are therefore unwelcome in human food. Here, an improved method for the microbiological assay of HA is reported; it makes use of the high mutagenic potency of HA in the Ames test and of the new Salmonella typhimurium strain YG1024 instead of strain TA98. The high sensitivity of the new strain is a consequence of its high acetyltransferase activity which results in a more efficient formation of genotoxic HA metabolites. The mutagenic activity of three selected HA in YG1024 is 10-20 times higher than that in TA98. This method can be used for the analysis of the HA content of food. A study of meat patties revealed significant differences in the mutagenic activity in the center and crust and of home-made and commercial patties; in both, the mutagenic activity was localized in the crust.