Detection of IQ-type mutagens in canned roasted eel

Basic extracts of canned roasted eel exhibited the highest mutagenicity among seven kinds of canned products assayed with Salmonella typhimurium TA98 in the presence of S-9 mix. The major mutagenic compounds of canned roasted eel extracts were purified and analysed by HPLC. The mutagenic fractions corresponding to the peaks of standard 2-amino-3,8-dimethylimidazo[4,5-f]quinoxaline(MeIQx) and 2-amino-3,7,8-trimethylimidazo[4,5-f]quinoxaline(7,8-DiMeIQx ) were further confirmed by the comparison of UV spectra, tester strain specificity and nitrite treatment. The estimated contents of MeIQx and 7,8-DiMeIQx were 1.1 ng and 5.3 ng per gram of canned roasted eel, respectively. Cooking temperature and time seemed to be the major factors affecting mutagen formation in fried eel. The type and amount of mutagenic compounds detected in canned roasted eel are likely to be correlated with the relative levels of specific free amino acids in raw eel.