Highly sensitive toxin microarray assay for aflatoxin B1 detection in cereals

We report a rapid, highly sensitive microarray method for quantitative aflatoxin B-1 (AFB(1)) detection in cereal samples. Following optimisation using an indirect competitive immunoassay, optimised amounts of AFB(1)-bovine serum albumin (AFB(1)-BSA)-conjugate were contact-printed onto 16 isolated sub-arrays on multi-pad nitrocellulose coated slides subsequently used in competitive binding assays. The toxin microarray working range for AFB(1) was established in the range of 15 pg g(-1) to 3.04 ng g(-1) with a detection limit of 1 pg g(-1). To determine assay sensitivity in contaminated food models, wheat flour and barley grains samples were spiked with AFB(1) standard dilutions. Following extraction, the working ranges of 0.11-4.15 and 0.18-4.31 ng g(-1) were determined, with detection limits of 30 and 90 pg g(-1), respectively. The sensitivity of the developed assay is below the European commission limit set for AFB(1) detection and the assay procedure was completed in 3 h time. Good recoveries (98% +/- 11%) obtained demonstrate the suitability of the proposed method for rapid and sensitive quantification of AFB(1) in contaminated cereal samples. (C) 2015 Elsevier Ltd. All rights reserved.