Aflatoxin M1 in raw milk in Qazvin Province, Iran: a seasonal study.

Occurrence of aflatoxin M1 (AFM1) was determined in 254 samples of raw milk obtained from dairy cow farms of Qazvin Province, Iran. Aflatoxin M1 analysis was carried out by using the competitive enzyme-linked immunosorbent assay technique for screening and high-performance liquid chromatography with fluorescence detection for confirmatory purposes. The limit of detection and quantification of the confirmatory method were 0.003 and 0.01 µg/l, respectively. Aflatoxin M1 was detected in 204 analysed samples (80.3%), ranging from 0.011 to 0.321 μg/l, and 144 samples (56.7%) had levels above the Iranian national standard limit of 0.050 μg/l. Considering the seasonal variability, the occurrence and levels of AFM1 in samples obtained in winter were significantly higher (P < 0.05) than those obtained in summer. The results of this survey indicate the usefulness of a monitoring programme to supervise food safety for consumers.