Fate of aflatoxin M1 during production and storage of parmesan cheese

The fate of AFM(1) during production of a long maturing cheese (Parmesan cheese) was assessed. Different levels of AFM(1) contamination and of the fat/casein (F/C) ratio of milk were considered, in order to evaluate if these factors can influence the enrichment factor (EF) of AFM(1) in cheese. For this purpose, 24 cheese-makings were carried out using naturally contaminated milk at 3 different AFM(1) levels and at 2 F/C ratios. AFM(1) analysis was performed by HPLC in raw milk, cream, cauldron milk, liquid cattle rennet, whey, curd and cheese at 3, 9, 16 and 24 months of ageing. The mass balances of the cheese-making processes were close to 100%; in whey, AFM(1) concentration was about 40% less than the concentration in cauldron milk. The EF in curd was between 4.0 and 5.2, with an average value of 4.7 +/- 0.4; this factor was not significantly affected by either AFM(1) contamination level or F/C ratio. During maturation, AFM(1) concentration and consequently EF increased from curd to 16 ageing months; successively, AFM(1) slightly decreased at 24 months and consequently the EF. At 3, 9, 16 months of maturation, the EF was significantly higher for cheeses prepared using milk with low F/C than those with high F/C milk; on the contrary, EF was not significantly influenced by the AFM(1) contamination level. In cheeses, EF values were between 4.7 and 6.3; from these results, the maximum admissible level for AFM(1) in Parmesan cheese should be about 0.275 mu g kg(-1). (C) 2015 Elsevier Ltd. All rights reserved.