Aflatoxin M1 contamination in dairy products marketed in Iran during winter and summer

In the present study, 298 dairy product samples consisting of pasteurized milk (91 samples), yoghurt (68 samples), white cheese (72 samples), butter (31 samples) and ice cream (36 samples) collected from popular markets in four large Iranian cities were examined for aflatoxin M-1 (AFM(1)) by thin layer chromatography (TLC) technique. The toxin was detected in 66 (72.5%) pasteurized milk samples (mean: 0.052 mu g/l; range: 0.013-0.250 mu g/l), 45 (66.1%) yoghurt samples (mean: 0.032 mu g/kg; range: 0.015-0.119 mu g/kg), 59 (81.9%) white cheese samples (mean: 0.297 mu g/kg; range: 0.030-1.200 mu g/kg), 8 (25.8%) butter samples (mean: 0.005 mu g/kg: range: 0.013-0.026 mu g/kg) and 25 (69.4%) ice cream samples (mean: 0.041 mu g/kg; range: 0.015-0.132 mu g/kg). The concentration of AFM(1) in 36.2%, 20.6%, 30.5%, 9.6% and 27.7% of pasteurized milk, yoghurt, white cheese, butter and ice cream samples, respectively, were higher than Iranian national standard limits. Levels of AFM(1) in samples of pasteurized milk, yoghurt, butter and ice cream collected in winter were significantly higher (P < 0.05) than those collected in summer. In the case of white cheese, level of AFM(1) was higher in winter than in summer, but the difference was not statistically significant (P > 0.05). The results indicated that the contamination of the dairy products in such a level could be a serious public health problem at the moment. (C) 2010 Elsevier Ltd. All rights reserved.