Fate of Aflatoxin M1 in Parmesan and Mozzarella Cheese.

Three batches each of Parmesan and mozzarella cheese were prepared, using milk which was naturally contaminated with aflatoxin M1. These cheeses were analyzed for aflatoxin M1 content at intervals while Parmesan was ripened for 43 weeks or mozzarella was stored for 17 weeks. There was a 5.8-fold enrichment of AFM1 in the Parmesan cheese over that in the milk from which the cheese was made. Apparent levels of aflatoxin M1 in Parmesan cheese started high, decreased until about the 22nd week of age and then slowly increased until the cheese was 43 weeks old, but the final concentration was less than that found initially. There was an 8.1-fold enrichment of AFM1 in mozzarella cheese over that in the milk from which it was made. Levels of aflatoxin M1 in mozzarella cheese varied slightly but remained near initial concentrations throughout the storage period.