Characterization of animal products according to geographic origin and feeding diet using nuclear magnetic resonance and isotope ratio mass spectrometry: cow milk

Six groups of six cows each, on two distinct sites, were fed on pasture and silage. Two analytical methods were employed, NMR to determine the proportions of polyunsaturated (PUFA), monounsaturated (MUFA) and saturated fatty acids (SFA) in milk fat and IRMS to measure the 18O enrichment of milk water. The fatty acid composition was sensitive to the diet while IRMS results were more influenced by the production area. A discriminant analysis showed that high resolution NMR and IRMS are two complementary methods suitable for the authentication of milk according to the feeding diet and geographic origin.