Aflatoxin M1 levels of some cheese varieties in Turkey.

Aflatoxins are generated by contamination of food and feed products by three Aspergillus spp.: Aspergillus flavus, Aspergillus parasiticus and Aspergillus nomius (8). Aflatoxin B 1 , B 2 , G 1 and G 2 are known as the chief aflatoxins. Aflatoxins are acute toxic, immunosuppressive, mutagenic, teratogenic and carcinogenic factors. Liver is the most affected organ by carcinogenic and toxic effects of aflatoxins (18). While Aspergillus flavus produces type B aflatoxins, other two produces both B and G types (27). Aflatoxin M 1 (AFM 1 ) and M 2 (AFM 2 ) are the hydroxylated metabolites of aflatoxin B 1 and aflatoxin B 2 (oxidative metabolic products). Aflatoxin B 1 can easily transferred to the milk of the dairy animals within 24-48 hours following feeding of the animals with AFM 1 contaminated fodder (22, 26). Aflatoxin M 1 has also similar carcinogenic and toxic effect in comparison to AFB 1 (15, 20). Aflatoxin may not only exist in milk but also in milk products. Because of the toxin’s affinity to the casein it exists widely in cheese (12, 16). Several ratios on the amount of AFM 1 transferred from milk to cheese had been reported and it is found that AFM 1 level in cheese is directly related to the technology, type and the eliminated water during the process (5-7, 16, 17, 19, 23). Numerous studies have been carried out on the AFM 1 level in cheeses sold in Turkey and in the other country. In addition to being inconsistent, generally a high concentration of AFM 1 level was determined (1, 2, 9, 12-14, 21, 24). The many milk products, produced in the other region (Edirne, Tekirdað, Balýkesir, Bursa etc.), are usually marketed in Istanbul, the biggest city of Turkey. Hence it gives Istanbul to represent the overall of Turkey. The present study has been performed in order to determine the AFM 1 levels in white cheese, processed cheese and kashar cheese in Istanbul.