Effects of temperature and time on mutagen formation in pan-fried hamburger.

Mutagenic activity generated in hamburger during pan-frying is dependent upon both temperature and time, with temperature appearing to be the more important variable. Uniformly prepared frozen hamburger pattie (115 g; 19% fat) were fried under carefully controlled conditions at 143 degrees C, 191 degrees C and 210 degrees C. Mutagenic activity assayed with the Ames test was not detected in uncooked hamburger, and in hamburger fried at 143 degrees C mutagenic activity remained low at all times studied (4--20 min). In contrast, frying at 191 degrees C or 210 degrees C for up to 10 min resulted in the generation of considerably higher levels of mutagenic activity. Mutagenic activity in fried hamburgers sold at selected restaurants ranged from very low to moderately high. Evidence is also presented for mutagenic inhibitory activity in uncooked and fried hamburger. Mutagenic inhibitory activity decreased mutagenesis mediated by liver S-9 from normal rats but not from Aroclor 1254-treated rats.