Validation of isotopic and elemental analyses of hard cheeses for origin traceability: international collaborative study

In compliance with the European law (EC N. 510/2006), geographical indications and designations of origin for agricultural products and foodstuffs must be protected against mislabelling. This is particularly important for Protection Denomination of Origin (PDO) hard cheeses, as Grana Padano and Parmigiano Reggiano, that can cost up to the double of the no-PDO competitors. A recent paper showed as Random Forests statistical models, based on isotopic and elemental composition, can trace the origin of 9 European and 2 extra-European cheeses in grated and shredded forms, for which it is not possible to check the logo fire-marked on the rind (Camin et al., 2012). The most significant variables for cheese traceability common in both models are δ13C, δ2H, δ15N, δ34S and Sr, Cu, Mo, Re, Na, U, Bi, Ni, Fe, Mn, Ga, Se, and Li. This work presents the results of an international collaborative study on the validation of isotopic and elemental analytical procedures organized in order to support their recognition as official methods, for establishing the authenticity of PDO cheeses. The collaborative study has been performed according to the IUPAC protocol and the ISO Standards 5725/2004 e 13528/2005.