The reduced mutagenicity of aflatoxin B1 due to hydroxylation: observations on five Salmonella typhimurium tester strains.

The mutagenicity of aflatoxin M1 relative to that of aflatoxin B1, the parent compound, was studied in 5 Ames' tester strains of Salmonella typhimurium (TA 98, TA 100, TA 1535, TA 1537, TA 1538). Aflatoxins B1 and M1 are both highly mutagenic in microsome-mediated system in TA 100. The prediction of the relative carcinogenicity of aflatoxin M1 to aflatoxin B1 posed by the mutation of TA 100 is probably more authentic than by TA 98.