The test utilises the recently released European Union Reference Laboratory for Animal Proteins (EURL-AP) recommended protocol for detection of horse DNA using real-time PCR. Using the EURL-AP’s recommended sequence-specific primers and probes for horse mitochondrial DNA, an assay has been developed with a limit of detection of around 0.01%.
Leatherhead CEO, Professor Paul Berryman, said: “Our scientists have been advising food companies on horsemeat contamination since the start of the scandal. We can now test for horsemeat in three different ways including ELISA plates and dipsticks, and now the EU-approved PCR DNA method. We have been particularly careful to check that the test is reliable and sensitive enough to give accurate and meaningful results. We are confident that our testing regimes are absolutely robust; and they are ideal for on-going surveillance programmes.”
Leatherhead’s Molecular Sciences Chief, Professor Brian Lake, explained: “A sample is considered positive at a level of 0.1% or above and an estimate of the percentage of horsemeat present in the sample can be provided by reference to an in-house standard. Multiple portions of each test sample are pooled to ensure that a representative sample is analysed. Positive and negative samples are included in each assay, together with a control to check for adequate extraction of DNA from the sample and for any inhibition of the PCR reaction by components of the sample. We can, of course, also give 1% threshold results if required.”
Dr Angus Knight, Leatherhead’s DNA expert, has highlighted the possible pitfalls of PCR horse DNA testing at conferences and he is well-reported in the trade press. The new Leatherhead horse testing regime has Dr Knight’s seal of approval.
