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

Abstract

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 M1 (AFM1) by using an enzyme linked immunosorbent assay (ELISA). Frequency of AFM1 and its concentration ranges in the ELISA positive samples were determined by high performance liquid chromatography with fluorescence detection (HPLC-FD). AFM1 contamination was 84.3%, 44.6% and 65.3% for cow, goat and sheep raw milks, respectively. Moreover, AFM1 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 AFM1 contamination in raw milk and dairy products were lower than that of ELISA. There were significant differences (P < 0.05) between the mean AFM1 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.