Real-time PCR for quantitative meat species testing

A method for quantitative meat speciation is described which combines the use of real-time PCR with species specific and ‘universal’ primers to measure individual species content and total meat content respectively. A comparison of the cycle number at which universal and species specific PCR products are first detected, in combination with the use of reference standards of known species content, is used as the basis for determining the percentage of a given species in a mixed sample. Importantly, the use of universal primers allows differences in DNA quality between samples and reference standards to be taken into account, while the use of real-time PCR allows measurement at an early stage in the PCR process which is inherently more accurate than the end point analysis associated with gel-based systems. This paper describes the quantification of beef in mixed samples to illustrate the principle of this approach.