δ34 S for tracing the origin of cheese and detecting its authenticity.

Casein δ34 S of 725 samples of cheese from all over the world were measured using IRMS. δ34 S alone made it possible to establish characteristic ranges of values for two types of Italian cheese (Grana Padano PDO and Parmigiano Reggiano PDO) and for the different regions and provinces of both the Grana Padano PDO and the Parmigiano Reggiano PDO zones. Moreover, δ34 S of PDO Italian samples were compared to both Italian (not PDO) and foreign competitive cheese samples. In all the cases, sulfur isotopic ratio analysis was a powerful tool to fix characteristic ranges of values for cheeses coming from different countries and to improve the information given by other isotopic parameters.