Contaminazioni da aflatossina M1nella filiera del latte ovino in Sardegna

The main objective of the thesis was to investigate the level of aflatoxin M1contamination in the dairy sheep sector in Sardinia (Italy). The first contribution was a survey on the level of aflatoxin M1contamination of small ruminant raw milk collected in Sardinia. Raw milk samples were collected at farm level from bulk tanks, from tank trucks and also at plant level from silo tanks. Overall were collected 517 sheep and 88 goat milk samples. Analysis for the detection of aflatoxins M1were performed using high-performance liquid chromatography. Only one sheep bulk tank milk sample exceeded the EU limit (50 ng/kg). The second contribution of the thesis was aimed to investigate the presence of aflatoxin M1of Pecorino Romano cheese and to compare the level of contamination with other long ripened cheeses produced using cow’s milk. A total of 108 Pecorino Romano, 40 Grana Padano and 32 Parmigiano Reggiano cheese samples were analyzed by high performance liquid chromatography-mass spectrometry. Only 5.6% of Pecorino Romano samples were above the detection limit of the method (30 ng/kg) but always within the maximum residues levels for long ripened cheeses (275 ng/Kg). The lower risk of aflatoxins M1contamination in dairy sheep milk sector as compared to dairy cow’s sector is due to differences in the farming systems, in the lower carry-over of small ruminants and in the greater impact of dilution effect in the milk picking system adopted by sheep milk plants.