Aflatoxin M1 in raw, pasteurized and powdered milk available in the Tehran market

Background and Aim: Milk and dairy products are fundamental components in the human diet, and may be the principle way for entrance of aflatoxins into the human body. Of all the mycotoxins, aflatoxin B1 (AFB1) is considered to be the most toxic and carcinogenic. Aflatoxin M1 (AFM1) may be found in the milk of animals that are fed on AFB1-containing feed. The purpose of this survey was to detect the levels of AFM1 in raw cow, sheep, and goat milk, and in pasteurized milk, and milk powder sampled at different locations in Tehran, and to compare these levels with maximum AFM1 limits adopted by European, USA, and Iran health organisations.Methods: The incidence of contamination of aflatoxin M1 (AFM1) in milk samples collected from the Tehran market was investigated by using the competitive enzyme linked immunosorbent assay (ELISA) technique.Results: A total of 100 samples composed of raw cow milk (60 samples), raw sheep milk (18), raw goat milk (7), pasteurized cow milk (8) and powdered milk (7) showed that 75% of tested samples were contaminated with various levels of AFM1 ranging from >35 to 756 ng/l. Percentages of AFM1-contaminated samples exceeding the American and European tolerance limits were 22% and 52%, respectively. The range of contamination was relatively higher in pasteurized milk than in raw cow and sheep milk. 70% of AFM1-contaminated pasteurized cow milk samples exceeded the European tolerance limit with a range of contamination between 89 and 756 ng/l. Percentages of contaminated raw cow, sheep and goat milk exceeding the European tolerance limit were 55%, 23% and 17%, respectively. Milk powder was almost free of AFM1 contamination with only one sample containing a concentration lower than the European tolerance limit (12 ng/l). Extrapolation of aflatoxin B1 (AFB1) from AFM1 levels of contamination in milk samples indicates that contamination in dairy cattle feeds may range from 0.5 to 47.8 µg/kg.Conclusion: The present study showed that there is a risk of milk being contaminated with AFM1 which consequently affects the public health in Tehran, since almost all the population, including infants and children, consume milk and milk products daily. Accordingly, the levels of AFM1 in milk and milk products should be controlled and monitored continuously. It is also important to maintain low levels of AFB1 in feeds of dairy animals.

Keywords:

Aflatoxin M1 (AFM1) , Milk , Contamination , ELISA