Fera has previously carried out proteomics development work (Defra projects FA0138 and FA0163) where a database of unique peptides for nine species was compiled. Using this database for data analysis, the proteomics approach developed in those projects was applied to highly processed meat mixtures enabling the detection of horse 0.5% (weight per weight, w/w) levels and pork at 1% level in beef. Using this work, we carried out further bioinformatics analysis to identify additional unique peptides, in particular for those species in our database with lower numbers of marker peptides. Experimental mass spectrometry analysis was then conducted to validate the new peptide sequences as markers of the correct species.
Now the database has been populated with sufficient unique peptides for the various meat species and these have been validated experimentally as good markers, further development work conducted allowed for the transfer of the method to a platform that is available to enforcement laboratories, such as triple quadrupole (QQQ) instruments. The identified marker peptides cano now be used to develop methods that target multiple species simultaneously, resulting in a “semi-targeted” approach where the analysis will screen for a range of species, enabling verification of the presence of declared species as well as detection of unknown adulterant species. Inter lab validation work has been performed to demonstrate transferability to different labs and to various instrument makes and models.