Highly sensitive toxin microarray assay for aflatoxin B1 detection incereals

We report a rapid, highly sensitive microarray method for quantitative aflatoxin B₁ (AFB₁) detection in cereal samples. Following optimisation using an indirect competitive immunoassay, optimised amounts of AFB₁-bovine serum albumin (AFB₁-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 AFB₁ was established in the range of 15pgg^-1 to 3.04ngg^-1, with a detection limit of 1pgg^-1. To determine assay sensitivity in contaminated food models, wheat flour and barley grains samples were spiked with AFB₁ standard dilutions. Following extraction, the working ranges of 0.11-4.15 and 0.18-4.31ngg^-1 were determined, with detection limits of 30 and 90pgg^-1, respectively. The sensitivity of the developed assay is below the European commission limit set for AFB₁ detection and the assay procedure was completed in 3h time. Good recoveries (98%±11%) obtained demonstrate the suitability of the proposed method for rapid and sensitive quantification of AFB₁ in contaminated cereal samples.