Evaluation of the concentration factor of aflatoxin M1 in a semi-hard Pecorino cheese obtained from naturally contaminated milk

Ewe's milk naturally contaminated with aflatoxin M1 (AFM1) at 0.024-0.117 μg/kg, was used to produce a semi-hard, ripened, Pecorino cheese. A predictive model to estimate the concentration of AFM1 in milk, by considering the values in cheese, was applied; furthermore, an AFM1 concentration in cheese, at different time of ripening, was investigated. The regression model showed a high correlation between the AFM1 amount in milk and its concentration in cheese. To establish the level of AFM1 contamination in milk, from taking into account the cheese AFM1 amount, a concentration factor of 4.13, with a confidence interval (CI) of 3.80-4.41, was obtained. The concentration index was constant during ripening. Thus, the model is a useful tool for the food business operator, when the competent authority carries out an official control, as prescribed by the European Commission Regulation No. 1881/2006.