Seasonal study of aflatoxin M1 contamination in milk of four dairy species in Yazd, Iran

• The occurrence of AFM1 in milk of four dairy species in Yazd province was assessed.
• The occurrence of AFM1 was the highest in cow milk than the milk of other species.
• The cow milk from industrial dairy farms is safer for human consumption.
• Seasonal variation influenced the occurrence of AFM1 in milk of dairy species.

This survey was conducted to determine the occurrence of aflatoxin M1 (AFM1) in samples of raw milk obtained from cow, sheep, goat, and camel herds in Yazd province during different seasons. Aflatoxin M1 was analyzed using the competitive enzyme-linked immunosorbent assay technique for screening and high-performance liquid chromatography with fluorescence detection for confirmatory purposes. The detection rates of AFM1 in cow, sheep, goat, and camel milk samples were 46.5%, 21.6%, 20.1%, and 4.03%, respectively. Levels of the toxin in 15.4% of cow milk, 11.5% of sheep milk, and 9.15% of goat milk samples exceeded the legal limit (0.050 μg/kg) recommended by the Institute of Standards and Industrial Research of Iran; while none of the camel milk samples exceeded the legal limit. The occurrence and levels of AFM1 in cow milk samples from industrial dairy farms was significantly lower (P ≤ 0.05) than those from traditional ones. Seasonal variations influenced the occurrence and levels of AFM1 in cow, sheep, and goat milk; however, no statistically significant seasonal effect was found for camel milk. This study indicates a high occurrence of AFM1 in cow milk especially those obtained from traditional dairy farms. Therefore, more supervision is required on these farms; and traditional dairy farms should be gradually replaced by industrial ones.