Reduction of Aflatoxin M1 during Production of Kashk, a Traditional Iranian Dairy Product

Background: Aflatoxin M1 (AFM1) is a toxic compound that could be found in milk and dairy products. AFM1 is the principle hydroxylated derivative of aflatoxin B1 (AFB1), formed in liver and excreted into the milk in the mammary glands of both human and lactating animals that have been fed with AFB1 contaminated diet. To the best of our knowledge, there is no report on stability of AFM1 during production of Iranian traditional kashk (ITK). This study designed to assess the effect of ITK processing on AFM1 content of cow’s milk artificially contaminated with AFM1. Methods: ITK making consisted of production of yogurt and strained yogurt, boiling the strained yogurt to make a curd and drying the resultant curd, according to common native procedure in Iran. AFM1 content of initial yogurt, strained yogurt and dried kashk was determined using high performance liquid chromatography (HPLC). Statistical analyses were performed by Student’s t-test and ANOVA using the SPSS 16.0 software package program. Results: The mean concentration of AFM1 in final ITK was determined as 0.118 ?g/kg which was significantly (p < 0.05) lower than that of initial milk, yogurt and strained yogurt samples. Also, AFM1 content of yogurt, strained yogurt and final ITK product was 46.12%, 6.94% and 48.24%, respectively lower than that of initial milk (p < 0.05). Conclusion: This study showed that ITK processing can effectively degrade AFM1 presented in initial raw milk and could be useful for minimizing AFM1 content of highly contaminated raw milk in dairy industries.