Identification of the species of origin of milk in cheeses by multivariate statistical analysis of polymerase chain reaction electrophoretic patterns

PDO Portuguese cheeses were used as a source of DNA for analysis by the polymerase chain reaction (PCR). Good quality DNA was extracted from all samples of milk and cheese and was suitable for PCR amplification at least of fragments up to 600 bp. The presence of caprine, ovine and bovine DNA was assessed using sets of species-specific primers. Electrophoretic patterns of PCR products were analysed with a computer-based method to obtain mobility values for each sample. These data were subjected to multivariate statistical analysis to evaluate the potential of this approach for authentication of dairy products. This enabled unequivocal discrimination between bovine, ovine and caprine milks and their derived cheeses.