MUTAGENIC ACTIVITY IN HEAT‐PROCESSED FOODS AS DETERMINED BY THE AMES SALMONELLA/MUTAGENICITY ASSAY

Different concentrations of six commercially available heat‐processed foods were screened for mutagenic activity using the Ames Salmonella mutagenicity assay. Bacterial strain TA 98 which detects frame shift mutations was used with S‐9 mix prepared from livers of Aroclor 1254 induced rats for metabolic activation. Cornflake cereal, branflake cereal, and a breakfast replacement product were not mutagenic at 90 g concentrations or less. At concentrations of 20 g or above, liquid smoke was toxic to the bacteria. At lower concentrations of 1 and 5 g the bacterial colony survival rate was low, therefore no conclusions were made regarding its mutagenic behavior. A canned brown gravy was not mutagenic at concentrations of 75 g or less. A canned au jus gravy displayed moderately high levels of mutagenic activity of 100 g concentrations or less. The contribution of manufacturers’processing techniques to the formation of chemical mutagens in foods is discussed.