Formation of mutagens in cooked foods. II. Foods with high starch content.

Mutagens, detectable Salmonella typhimurium TA98 and TA100 after activation by liver S-9 fraction, are formed when starchy foods are cooked. Potatoes were fried and breads were toasted, baked and fried to produce mutagenically active substances. While toasting both white bread and dark bread produce the mutagens at the same initial rate, dark bread products much higher levels of mutagenicity when toasted for long times. Significant mutagenic activity is produced when starchy foods are prepared by common cooking procedures.