ORIGINAL PAPER Aflatoxin M 1 contamination in commercial pasteurized milk from local markets in Fariman, Iran Bamdad Riahi-Zanjani & Mahdi Balali-Mood Received: 7 August 2013 /Revised: 19 August 2013 /Accepted: 23 August 2013 /Published online: 12 September 2013 # Society for Mycotoxin Research and Springer-Verlag Berlin Heidelberg 2013 Abstract Contamination of milk and dairy products with af- latoxin M 1 (AFM 1 ) presents a risk for human health. The aim of this study was to investigate the presence of AFM 1 in pasteurized milk samples in Fariman, located in the province of Khorasan Razavi, Iran, by enzyme-linked immunosorbent assay (ELISA). Forty-five samples of pasteurized milk from different supermarkets were collected during 3 months in sum- mer (July to September, 2012). AFM 1 contamination was detected in all of milk samples. The mean concentration of aflatoxin M 1 was 27.2 ng/l. The range of AFM 1 content was 8.8–64 ng/l. Thirteen (28.8 %) of the samples had AFM 1 levels exceeding the maximum levels (50 ng/l) accepted by the European Union. Due to the fact that milk is used by all the age groups including infants and children in Fariman city, it is necessary to minimize the health risk from AFM1 contamina- tion in milk. For this reason, the level of its precursor, aflatoxin B 1 (AFB 1 ), in dairy feeds must be reduced, requiring constant aflatoxin monitoring of relevant agricultural commodities. Keywords Aflatoxin M 1 . Pasteurized milk . ELISA . Fariman . Iran Introduction Aflatoxins are secondary toxic metabolites produced in food by toxigenic fungi such as Aspergillus flavus and Aspergillus parasiticus . Fungal spores in the environment and inadequate storage of foodstuffs provide favorable conditions for the growth of fungi. Many studies have shown that nuts, cereals and rice could be contaminated by Aspergillus species (Rostami et al. 2009). Increased levels of aflatoxins in food and feed commod- ities are usually related to high humidity and warm temperatures (Adams and Moss 2005). Aflatoxins have been suggested as immunosuppressive, mutagenic, teratogenic and carcinogenic compounds to animals and humans (Kocabas and Sekerel 2003). They can cause DNA damage, gene mutation, chromo- somal anomalies and cell transformation in mammalians cells in vitro, in insects and in bacteria (Prandini et al. 2009). Aflatoxin M 1 (AFM 1 ) is a metabolite of aflatoxin B 1 that could be found in milk when dairy cattle are fed with contam- inated feedstuff (Creppy 2002). It is formed in liver by the hepatic microsomal mixed-function oxidase system (Gallagher et al. 1996). There is a direct relationship between the level of AFM 1 in milk and AFB 1 in feed consumed by dairy cattle (Bakirci 2001). Contamination of milk and dairy products to AFM 1 can increase the risk of hepatocellular carcinoma (Peraica et al. 1999). The International Agency for Research on Cancer (IARC) of WHO classified aflatoxins B 1 and M 1 as group 1 human carcinogens (Cathey et al. 1994; Dragacci et al. 1995, IARC 2002). Many countries have established provi- sions to control the levels of aflatoxins in feeds and foods to reduce their hazards (Sarimehmetoglo et al. 2004). The European Community (EU) and Codex Alimentarius Commission (CAC) recommended that the maximum level of aflatoxin M 1 in milk and milk products should not exceed 50 ng/l (CAC 2001; EU 2010). In the Iranian food standard, AFM 1 levels in pasteurized milk were limited to 50 ng/l, similar to EC regulations (Institute of Standards and Industrial Research of Iran 2002). Although there are some sporadic studies about the contamination of AFM 1 in milk and dairy products in different cities of Iran (Karimi 1998; Oveisi et al. 2007; Sefidgar et al. 2008; Fallah et al. 2009; Ghazani 2009; Kamkar et al. 2011), there are no data on AFM 1 contamination in pasteurized milk produced in Fariman City, which is situated in the Northeast of Iran. B. Riahi-Zanjani : M. Balali-Mood (*) Medical Toxicology Research Center, School of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran e-mail: mbalalimood@hotmail.com Mycotoxin Res (2013) 29:271–274 DOI 10.1007/s12550-013-0179-6