A TaqMan real-time PCR system for the identification and quantification of bovine DNA in meats, milks and cheeses

Accurate quantitative assays are required for enforcing food labelling procedures and preventing food ingredient contamination, misdescription and fraud. Simplex and duplex TaqMan real-time PCR systems have been tested for the identification and quantification of DNA in meat, milk and cheese. DNA was isolated from meat and cheese using a standard CTAB protocol and from milk using a Promega Wizard Magnetic kit and purified by Qiagen silicon spin columns. High quality DNA isolated from beef mince was used for standard curve construction in the TaqMan real-time PCR assay using a bovine-specific primer pair for the mitochondrial cytb gene and a FAM-labelled mammalian-specific cytb probe. The real-time PCR assay can quantitatively detect as little as 35 pg bovine DNA and showed no cross-reaction with ovine, caprine or porcine DNA. The system has been successfully used to measure bovine DNA in fresh and processed meat, milk and cheese, and will prove useful for bovine species identification and quantitative authentication of animal-derived products.