Contamination of UHT milk by aflatoxin M 1 in Iran

Abstract

In this study the levels of aflatoxin M 1 (AFM 1) in UHT milk samples were determined in May, August and November and February. Two hundred and ten UHT milk samples were obtained from supermarkets in Tehran, Iran. The occurrence and concentration range of AFM 1 in the samples were investigated by competitive enzyme-linked immunoabsorbent assay (ELISA) method. AFM 1 was found in 116 (55.2%) of 210 UHT milk samples examined. The levels of AFM 1 in 70 (33.3%) samples were higher than the maximum tolerance limit (0.05 μg/l) accepted by some European countries while none of the samples exceeded the prescribed limit of US regulations. The highest mean concentration of AFM 1 was recorded in February (0.087 μg/l). The lowest mean concentration of AFM 1 was recorded in August (0.021 μg/l). Statistical evaluation showed that there were significant difference ( P < 0.01) between the mean concentrations of AFM 1 of UHT milk samples taken in February with May and August. AFM 1 contents of milk samples taken in February were not higher than UHT milk samples taken in November ( P < 0.01). The AFM 1 incidence of exceeding legal limit in UHT milk samples (33.3%) was relatively much higher than some other countries. It was therefore concluded that, the levels of AFM 1 in UHT milk samples consumed in Iran were high and seemed to pose a threat to public health.