Occurrence of aflatoxins B1, B2, G1 and G2 in cooked food components of whole meals marketed in fast food outlets of the city of Sa~o Paulo, SP, Brazil

Samples of cooked components of regular meals served at fast food outlets of the city of Sa~oPaulo, Brazil were analysed for aflatoxins B₁, B₂, G₁ and G₂. The 322 samples were composed of prepared traditional Brazilian and ethnic foods in which aflatoxins might be present. Thin-layer chromatography was used for separation of the compounds and their determination was achieved by both long wave UV light and fluorodensitometry. Aflatoxins were detected in 30 samples (9.31% of the total) in a range of 2.80 to 1323 ng/g for B_{1 +} B_{2 +} G_{1 +} G₂ with 90th percentiles of 158 (B_{1 +} G₁) and 258 (B_{1 +} B_{2 +} G_{1 +} G₂). Aflatoxin B₁ was detected in all contaminated samples. The contamination levels and frequency of aflatoxins B₁ and G₁ in positive samples above 20 ng/g in this study are high, indicating that there is a certain degree of exposure of the population to the carcinogenic aflatoxin.