Aflatoxin M1 in milk and traditional dairy products from west part of Iran: Occurrence and seasonal variation with an emphasis on risk assessment of human exposure

In the present study, a total of 358 samples consisting of raw milk of cow (n = 64), goat (n = 56) and sheep (n = 52); traditional cheese (n = 40), yoghurt (n = 42), Kashk (n = 40), Doogh (n = 44) and Tarkhineh (n = 20) were analyzed for aflatoxin M-1 (AFM(1)) by using an enzyme linked immunosorbent assay (ELISA). Frequency of AFM(1) and its concentration ranges in the ELISA positive samples were determined by high performance liquid chromatography with fluorescence detection (HPLC-FD). AFM(1) contamination was 84.3%, 44.6% and 65.3% for cow, goat and sheep raw milks, respectively. Moreover, AFK(1) was in 65.5%, 23.8%, 14%, 13.6% and 35.0% of cheese, yoghurt, Kashk, Doogh and Tarkhineh samples, respectively. Percentages of cow milk, goat milk, sheep milk and cheese samples exceeding the EU limit were 35.9%, 11.1%, 26.9% and 10%, respectively. HPLC analyses confirmed the ELISA results although the percentages of AFM(1) contamination in raw milk and dairy products were lower than that of ELISA. There were significant differences (P < 0.05) between the mean AFM(1) contents of raw milk, cheese and yoghurt samples during winter and summer seasons. Our study demonstrated that there is a potential risk for liver cancer due to the consumption of milk and dairy products in Iranian consumers. (C) 2015 Elsevier Ltd. All rights reserved.