Evaluation of aflatoxin B1 levels in TMR and aflatoxin M1 levels in raw milk by ELISA and HPLC

Aspergillus flavus, A. parasiticus and A. nomius are the most important aflatoxin-producing species of B1, B2, G1 and G2 in food and feed. M1 and M2 Aflatoxins are the hydroxylated metabolites of B1 and B2 aflatoxins. The aim of this study was to evaluated the amount of aflatoxin B1 in animal feed and its relationship with aflatoxin M1 in raw milk. For this purpose, 20 industrial and 20 semi-industrial farms were selected and a sample of TMR ration and raw milk of each farm was sampled separately. Aflatoxin B1 in feed and Aflatoxin M1 in milk were evaluated by competitive ELISA, and the samples with values above maximum residue limit (MRL) were evaluated by high performance liquid chromatography (HPLC). The ELISA results showed that 35% of industrial farm feed and 75% of semi-industrial farm feed were contaminated with aflatoxin B1, of which 5% and 15% of industrial and semi-industrial farm had values above MRL, respectively. Also, in evaluating the amount of aflatoxin M1 in produced milk, it was found that aflatoxin M1 was observed only in the milk of farms that were positive for aflatoxin B1 and this rate was 20% and 55% in industrial and semi-industrial farms, respectively. The samples of milk with values above MRL were measured by HPLC confirmation test, which indicates that none of the samples of industrial and semi-industrial dairy production milk had higher values (0.5 ng/ml). Due to the importance of per capita milk consumption in the community diet and the dangers of aflatoxin M1 in it, extensive and accurate monitoring of milk production and supply centers as well as dairy factories is essential.