Application of polymerase chain reaction for detection of goats' milk adulteration by milk of cow

Abstract

Numerous methods based on DNA analysis have been employed in the food industry to monitor adulterations of food products of animal origin. Among them the most frequently used are: polymerase chain reaction (PCR) amplification of a marker gene fragment(s) with universal primers, or amplification of DNA with species-specific primers. PCR-products of different origin can be discriminated by size, restriction fragment length polymorphism (RFLP) or single stranded conformational polymorphism (SSCP) analysis. These methods have been used for identification, and differentiation between, the animal origins of raw or heat-treated meat and meat products (Chikuni et al. 1994; Meyer et al. 1994, 1995; Zehner et al. 1998; Behrens et al. 1999; Guoli et al. 1999; Hopwood et al. 1999; Matsunaga et al. 1999; Wolf et al. 1999). These approaches are also applicable to the analysis of dairy products. However, adulterations of goats' milk and its products are traditionally tested by immunological and/or electrophoretic methods (Amigo et al. 1992; Levieux & Venien, 1994; Mimmo & Pagani, 1998). So far, only a few DNA-based techniques designed to detect the presence of bovine DNA in goats' milk have been described (Plath et al. 1997; Branciari et al. 2000). This paper presents a one-step PCR procedure for detection of adulteration of goats' milk with cows' milk. The method, employing bovine-specific primers for amplification of a 274 bp fragment of cytochrome b DNA, seems to be simple, fast, specific and sensitive.