PCR-based detection of cow and goat milk in sheep milk and dairy products marketed in Mashhad city of Iran

Abstract

BACKGROUND: The extensive consumption of milk and<br />dairy products makes these foodstuffs targets for potential<br />adulteration with financial gains for unscrupulous producers.<br />OBJECTIVES: The aim of this study was using PCR assay to<br />detect cow milk in labeled sheep milk, sheep yoghurt, and<br />Lighvan cheese (a traditional ripened cheese produced from<br />sheep's milk). METHODS: The assay utilized primers targeting<br />the mitochondrial 12s and 16s rRNA gene. In this study, 35<br />samples of sheep milk, 35 samples of sheep yoghurt, and 35<br />samples of Lighvan cheese were purchased from different<br />supermarkets in Mashhad city with different batch numbers.<br />RESULTS: The results showed only 21 out of 105 (20%) samples<br />contained pure sheep milk. Undeclared presence of cow and goat<br />milk was detected in 33(31.5%) and 68(65%) of the 105 samples,<br />respectively. CONCLUSIONS: It seems the PCR based analytical<br />method is an applicable technique to monitor adulteration in<br />dairy products.