Discrimination markers for the geographical and species origin of raw milk within Romania

Isotopic and elemental compositions of raw bovine and ovine milk samples from three farms situated in Transylvania were investigated to see how differences in water composition and feeding regime were reflected in the milk samples. By applying chemometric analysis, a marker association suitable for the origin and species differentiation of raw milk samples is proposed in this pilot work. The most powerful combination of markers involved isotope ratios of oxygen (18O/16O) and carbon (13C/12C) combined with Sr and Mn concentrations. Also, the species differentiation between bovine and ovine milk products was made by the corroboration of Sr concentration with isotope ratio of hydrogen. The results obtained from cross-validation showed that resulting models of discriminant analysis allowed the correct classification of 90.9% of samples related to geographical origin, while for raw milk speciation the correct classification percentage was 96.4%.