Applicability and sensitivity of PCR-SSCP method for milk species identification in cheese

Species identification in food has become a prominent issue in recent years as the importance of consumer protection has increased. DNA-based species identification methods were developed by researchers in the last two decades, as these are reliable, accurate, and low-cost techniques for species identification in raw and processed food products as well. In our study, universal primers were designed to conserved regions of mitochondrial 12S rRNA. Amplicons were heat-denatured and a PCR single strand conformation polymorphism (SSCP) method was developed to identify cattle, buffalo, sheep, and goat DNA. Sensitivity of this technique was tested on DNA mixtures of cattle-sheep, cattle-goat, and cattle-buffalo and the threshold limit of cattle DNA was 5%, 5%, and 3%, respectively. One hundred and five cheeses were purchased and collected from Bosnian and Hungarian farmers, retails, and supermarkets to reveal fraud, 32 percent of them (34 cheeses) were found to be mislabelled by species.