Safety and efficacy evaluation of aqueous citric acid to degrade B-aflatoxins in maize

Chemical inactivation of aflatoxin B1 (AFB1) and aflatoxin B2 (AFB2) in maize grain by means of 1 N aqueous citric acid was confirmed by the AFLATEST™ immunoaffinity column method, high performance liquid chromatography (HPLC), and the Ames test (Salmonella-microsomal screening system). The AFLATEST™ assay showed that aflatoxins in the maize grain with an initial concentration of 29 ng/g were completely degraded and 96.7% degradation occurred in maize contaminated with 93 ng/g when treated with the aqueous citric acid. Aflatoxin fluorescence strength of acidified samples was much weaker than untreated samples as observed in HPLC chromatograms. On the other hand, the Ames test results indicated that the mutagenic activity of acidified samples was greatly reduced compared with that of untreated samples based on his− → his+ reversions in the Salmonella TA100 strain. Chemical inactivation appears to be a promising method of removing aflatoxin from food commodities.