Occurrence, seasonal variation and risk assessment of exposure to aflatoxin M1 in Iranian traditional cheeses

A total of 360 traditional cheeses consisted of Lighvan (n = 62), Koozeh (n = 62), Siahmazgi (n = 58), Khiki (n = 58), Talesh (n = 58) and Lactic (n = 62) collected from different parts of Iran were analyzed for aflatoxin M1 (AFM1) using an enzyme linked immunosorbent assay (ELISA). Frequency of AFM1 and its concentration ranges of all the ELISA positive samples were determined by high-performance liquid chromatography with fluorescence detection (HPLC-FD). AFM1 was detected in 60.3%, 75.8%, 72.4%, 43.5%, 38.7% and 35.4% of Siahmazgi, Khiki, Talesh, Lighvan, Koozeh and Lactic cheeses, respectively with concentration ranging from 50.5 to 308.7 ng/kg, respectively. HPLC analyses confirmed the ELISA results although the rates of contaminated cheese samples were lower than that of ELISA. There was significant difference in AFM1 level between various cheese types and samples collected from summer and winter seasons (P < 0.05). By comparing our findings with the EU limit, about 10.5% of cheese samples had exceeding values for the toxin. The results of the present study indicates that there is no health risk in consumption of Iranian traditional cheeses due to the presence of AFM1.