Quantification of aflatoxins in corn distributed in the city of Monterrey, Mexico

In this study kerneled corn sold and distributed through wholesale outlets in the city of Monterrey, Mexico was analysed. The extraction of aflatoxins was performed with a mixture of methanol/water (80:20) and its derivatization was carried out with trifluoroacetic acid. The analysis was done by high performance liquid chromatography (HPLC) using fluorescence for detection. From the 41 samples analysed, aflatoxins B1 and G1, were found to be present. Aflatoxin B1 concentrations ranged from 5.03 ng/g to 465.31 ng/g, aflatoxin G1 concentrations ranged from 1.59 ng/g to 57.1 ng/g. It was found that 87.8% of the samples were contaminated with aflatoxins: in addition, 58.5% contained levels above Mexican legal limits which are, at present, 20 ng/g.