A spore-based miniaturized novel assay for rapid aflatoxin detection in milk

Aflatoxin M1 contamination in milk and dairy products is a major issue worldwide. Aflatoxin is a carcinogen that enters into the milk through animals feed. Here, Bacillus megaterium spores were immobilized on gold-coated chip followed by addition of pre-treated milk and the diacetate fluorescein as fluorogenic substrate. Fluorescence was measured semiquantitatively using a cyan fluorescent protein filter at 430 nm and 470 nm. Results show that milk is positive for aflatoxin at concentrations higher than 0.1 μg/L. The developed assay was evaluated with raw and pasteurized milk samples. Comparison of aflatoxin M1 concentration data with a rapid one-step assay showed correlation of 0.98. This spore-based miniaturized assay on gold-coated chip can thus be used for real-time analysis of aflatoxin M1 in milk with lowest detection limit of 0.1 μg/L within 25 min.