Mutagenic activity in rat urine after feeding with the azo dye tartrazine.

The azo dye tartrazine, after dosing by gavage, is transformed by rats into urinary metabolites which exert dose-dependent mutagenic activities in the Ames test with Salmonella typhimurium TA 98 after addition of rat liver metabolizing enzymes (S9 mix). The strain TA 100 showed no mutagenic response.