Determination of Seasonal Distribution of Aflatoxin M-1 Level in Cheese Production

The aim of this study was to determine the Aflatoxin M-1 (AFM(1)) quantities in raw milk samples and cheese samples produced from the same lot. The samples were obtained from six dairy plants in four different seasons. AFM(1) amounts of the samples were assessed by a Reverse-Phase High Performance Liquid Chromatography (RP-HPLC) device with fluorescence detector, using a preliminary immune affinity column (IAC) for post-column derivatization and these values were compared with legal limits. Average of AFM(1) values of raw milk samples were determined to be 41.9 ng/l, 31.3 ng/l, 68.5 ng/l and 92.0 ng/I in spring, summer, autumn, and winter, respectively. 54.2 % of the investigated milk samples exceeded legal limits. AFM(1) concentrations were higher during the autumn and winter. Average values of AFM(1) in cheese samples were determined to be 92.7 ng/kg, 72.3 ng/kg, 190.6 ng/kg and 255.8 ng/kg in spring, summer, autumn, and winter, respectively. AFM(1) was at levels of 1.25 to 5.18-fold higher than those presented in the raw milk used for the cheese production. Based on the admissible limit, 16.7 % of the cheese samples were shown to have exceeded this valid maximum limit value. Consequently, it was found that seasonal change had a significant effect on the amount of AFM(1).