Use of milk fatty acids composition to discriminate area of origin of bulk milk

The fatty acid composition of cow milk, collected in a survey from 19 dairy farms in the border area between Italy and Slovenia, was investigated for 2 consecutive years (2005 and 2006) to assess the possibility of discriminating the area of the origin of the milk. Farms were selected based on diet, animal breed, and farm management to represent the local variability of the systems. In Slovenian farms, grass silage and hay prevailed over corn silage and concentrate feeds, whereas in Italian farms, hay and concentrates were the predominant components of the diet. Fifty-three fatty acids were separated and quantified in Italian and Slovenian milks. Saturated fatty acids represented the most abundant class, followed by monounsaturated and polyunsaturated fatty acids. Significant differences were observed between Italian and Slovenian milks for the concentration of 40 fatty acids, whereas significant differences were observed between years of production for 15 fatty acids. Discriminant analysis was used to identify a classification criterion of milk, using country and year of production as grouping variables. Considering statistical results and the scatter plot of the scores of the first 2 functions, the best discriminant criteria were those based on unsaturated fatty acids and on fatty acids with several carbon atoms ≥18.