New Method for the Simultaneous Identification of Cow, Sheep, Goat, and Water Buffalo in Dairy Products by Analysis of Short Species-Specific Mitochondrial DNA Targets

A novel method is presented here as an analytical tool for food control and authentication of dairy products manufactured from the milk of cow, sheep, goat, and buffalo. The method is based on multiplex polymerase chain reaction (PCR) of species-specific mitochondrial DNA (mtDNA) targets followed by fragment size analysis by capillary electrophoresis. The method includes (a) simultaneous detection of four species, (b) internal control for DNA extraction and PCR, (c) mtDNA as a target for PCR, (d) amplicons of <200 bp, and (e) flexibility in the electrophoresis and fragment size detection method. Species identification proved to be straightforward, efficient, sensitive, and robust. The method is sensitive to an at least 1% (v/v) relative proportion of milk in binary mixtures. A survey of commercial products showed that 12.5% failed to conform to the description of the contents, by either the introduction or absence of listed species, thus demonstrating the relevance of this type of testing.