A direct competitive enzyme-linked immunosorbent assay (dc-ELISA) was developed for the determination of total amount of aflatoxin B1, B2, G1 and G2 (AFB1, AFB2, AFG1 and AFG2), using a mouse monoclonal antibody that shows similar reactivity to each of these AFs. The working range of the developed dc-ELISA was 50-230 pg/mL for AFB1, 50-270 pg/mL for AFB2, 60-390 pg/mL for AFG1 and 65-700 pg/mL for AFG2. The recovery of AFs from spiked roasted peanuts was 98％. Further, when 4 samples actually contaminated with AFB1, AFB2, AFG1 and AFG2 were examined, the results of dc-ELISA were highly correlated with the values assigned by the Food Analysis Performance Assessment Scheme. The developed dc-ELISA appears to be suitable for the determination of total AFs at concentrations around the maximum permitted level (10 μg/kg for all foods) in Japan.
Keywords: ELISA; aflatoxin; immunoassay; monoclonal antibody; total aflatoxin.