An ultra-sensitive monoclonal antibody-based competitive enzyme immunoassay for aflatoxin M1 in milk and infant milk products

A sensitive and specific monoclonal antibody (Mab) against aflatoxin M-1 (AFM(1)) named as 2C9 was selected by semi-solid HAT medium It exhibited high affinity for AFM(1) of 1 74 x 10(9) L/mol and no cross-reactivity to aflatoxin B-1 B-2 G(1) and G(2) Based on the antibody an ultra-sensitive competitive enzyme-linked immunosorbent assay (ELISA) was developed for AFM(1) in milk and infant milk products Assays were performed in the AFM(1)-BSA coated (0 0625 mu g/mL) ELISA format in which the antibody was diluted 1 10 000 Several physicochemical factors (pH ionic strength and blocking solution) that influence assay performance were optimised Finally the limits of detection were 3 ng/L for milk and 6 ng/L for milk-based cereal weaning food inter-assay and intra assay variations were less than 10% and the recovery ranged from 91% to 110% Thirty samples were analysed and concordant results were obtained when the data were compared with a reference high performance liquid chromatography method (C) 2010 Elsevier Ltd All rights reserved