Enzyme-assisted extraction of aflatoxin M1 in Brazilian artisanal cheese using reversed-phase liquid chromatography

Brazil is an influential and successful food-producing country, where we can highlight artisanal cheeses gaining visibility in foreign markets. Some of these cheeses are made from raw milk, making them susceptible to contamination by microorganisms, including fungi, which can produce harmful mycotoxins. Feed contaminated with aflatoxin B1, when consumed by dairy animals, is metabolized and transformed into aflatoxin M1 (AFM1), which is excreted in milk. Therefore, the aim of this research was to investigate the occurrence of AFM1 in artisanal cheeses from two Brazilian states: Minas Gerais and São Paulo. This toxin was extracted from 10 g of sample and 50 ml pepsin solution. An aliquot of the extract was passed through an immunoaffinity column, eluted, and dried under nitrogen. For the analysis of the detection and quantification of AFM1, the High-Performance Liquid Chromatography (HPLC) fluorescence detection system was used. A total of 130 samples were analyzed; 41 tested positive for AFM1, while 89 were negative. Out of 41 positive samples, only two were above the maximum tolerated limit by ANVISA of 2.5 µg/kg. These results show the importance of investigating the occurrence of AFM1 in artisanal cheeses, aiming to prevent and increase food safety.