Distribution and stability of aflatoxin M-1 during processing, ripening and storage of Telemes cheese

Abstract

Telemes cheeses were produced using milk that was artificially-contaminated with aflatoxin M-1 at the levels of 0.050 and 0.100 mug/l. The cheeses produced in the two cheese-making trials were allowed to ripen for 2 months and stored for an addition al 4 months to simulate commercial production of Telemes cheese. Concentrations of aflatoxin M-1 in whey, curd, brine, and the produced cheeses were determined at intervals by liquid chromatography and fluorometric detection coupled with immunoaffinity column extraction. Concentrations of aflatoxin M-1 in the produced curds were found to be 3.9 and 4. 4 times higher than those in milk, whereas concentrations in whey were lower than those in curd and milk. Aflatoxin M-1 was present in cheese at higher concentrations at the beginning than at the end of the ripening/storage period, and it declined to concentrations 2.7 and 3.4 times higher than those initially present in milk by the end of the sixth month of storage. Concentrations of aflatoxin M-1 in brine started low and increased by the end of the ripening/storage period but only a portion of the amounts of aflatoxin M-1 lost from cheese was found in the brine. Results showed that Telemes cheeses produced from milk containing aflatoxin M-1 at a concentration close to either the maxim um acceptable level of 0.05 mug/l set by the European union (EU) or at double this value, will contain the toxin at a level that is much lower or slightly higher, respectively, than the maximum acceptable level of 0.250 mug of aflatoxin M-1/kg cheese set by some countries.