Occurrence of aflatoxin M1 in Iranian white cheese

Aflatoxins are mold secondary metabolites produced by species of Aspergillus. Aflatoxin causes acute and/or chronic poisoning and exhibits carcinogenic، mutagenic and teratogenic effects. Lactating cows fed with B1 aflatoxin-contaminated feed transmit the toxin، as the metabolic form aflatoxin M1 (AFM1) to the milk. When cheese is made from AFM1 contaminated milk، the toxin can be carried over to cheese. In this cross - sectional study، 188 samples were obtained from market in summer and winter and AFM1 levels were determined by ELISA method. AFM1 was found in 133 (70. 7%) samples. The mean of AFM1 concentration was 343 ng / kg. AFM1 levels in 68 samples (36. 2%) exceeded the maximum tolerance limit accepted by some European countries. Statistical analysis showed that concentration of AFM1 in cheese samples taken in winter (495 ng/kg) were significantly (p < 0. 05) higher than those taken in summer (191 ng/kg). In conclusion، incidence of AFM1 was high among cheese samples what must be regarded as a health concern for consumers.