The results of horsemeat tests conducted by the FSA and local authorities are comparable even though a range of DNA methodologies were used, a Defra report has insisted.
There is little standardisation of tests at the moment, with different methods having different limits of detection (LOD) that are also expressed differently - as DNA copy numbers or weight-in-weight tissue sample measurements.
The LOD of methods used in the FSA’s survey therefore needed to be “robustly tested and qualified so results obtained for samples can be interpreted with confidence,” said the Defra report, carried out by the Government Chemist.
The methodologies tested were PCR-CE, PrimerDesign and Neogen BioKits, which have different validated LODs. But the report found they were all capable of reaching an LOD of less than 0.1% weight-in-weight for raw horsemeat in raw beef “if quality procedures and good laboratory practice” were adhered to.
However, it warned that more guidance was needed on how to compare levels of meat adulteration from different testing methodologies used across Europe.