CHAPTER 20: Horse Meat: The International Collaborative Trial of the Real-time PCR Method for the Quantitation of Horse DNA

Following the UK–European Union (EU) horse-meat incident of 2013, where a significant amount of horse DNA was found in a beef burger product on sale at a supermarket store, a real-time polymerase chain reaction (PCR) approach for the quantitation of horse DNA was developed at LGC (UK) using Department for Environment, Food and Rural Affairs (Defra) funding. A Food Standards Agency (FSA)-funded international collaborative trial of the method [based on International Union of Pure and Applied Chemistry (IUPAC) and European Network of Genetically Modified Organism Laboratories (ENGL) guidance] was organised in order to evaluate the repeatability and reproducibility of the method within and between laboratories. Participants returned results based on the evaluation of five blindly labelled test samples [representing samples with 0.1, 0.5, 1, 5, and 20% (w/w) horse meat in a beef meat background] relative to a calibration curve. This case study describes the results of the collaborative trial and illustrates how the results of the trial conform to published guidance and acceptance criteria for real-time PCR methods subject to inter-laboratory trials. Following qualification of this method as being fit for purpose as a result of the International Collaborative Trial, the method is now being considered for international standardisation through the relevant Comité Européen de Normalisation (CEN) sub-committee.