Distribution of aflatoxin M1 during Grana Padano cheese production from naturally contaminated milk

The distribution of aflatoxin M1 (AFM1) has been investigated in samples of whey, curd and a typical hard and long maturing cheese like Grana Padano (ripened for twelve months), produced with naturally contaminated milk in a range of 30–98 ng AFM1/kg. AFM1 determinations were carried out on 25 samples of each product by reverse-phase HPLC and fluorescence detection with post-column derivatisation, after a preliminary C18-SPE clean-up. Experimental results show that, in comparison to milk, AFM1 concentration levels increased both in curd (3-fold) and in long maturing cheese (4.5-fold), while AFM1 occurrence in whey decreased by 40%.These data suggest that AFM1 concentration in milk could be a good predictor of its fate in milk products.