Mutagenicity of market basket samples for a total diet study

The mutagenicity of cooked foods was investigated by using the market basket samples collected for a total diet study. Eighty-nine foods were divided into thirteen groups and cooked. These cooked food groups were treated with amyloglucosidase, hesperidinase, pectinase or papain, and extracted with methanol. The crude methanol extracts were successively extracted with n-hexane and diethyl ether under acidic conditions and also extracted with diethyl ether under basic conditions. The mutagenicity of each extract was assayed by means of the Ames test. All food groups except the rice group, and the fat and oil group were mutagenic in Salmonella typhimurium strain TA98 or TA100 with or without S9mix. Quercetin was detected in some groups by gas chromatography-mass spectrometry, but other kinds of mutagens in the cooked foods were not detected. According to this total diet study, Japanese people daily ingest mutagenic substances, which are mainly derived from fruits (33% of the total mutagenic activity for strain TA100 in the presence of S9mix), fish and shellfish (24%), pulses (15%), and meats (13%).