Proteomics/peptidomics, powerfull analytical approaches in feed safety and authentication assessment
We set up a promising MS-based method to determine the species and the source (legal or not) present in PAPs: a TCA-acetone protein extraction followed by a clean-up step, an in-solution tryptic digestion of 5 hours and mass spectrometry analyses without any a priori with a Q-TOF. We were able to identify some species-specific biomarkers peptide (in beef, pork, sheep and poultry), representative of these MBM. Among these, 3 bovine and 4 porcine peptides were selected for the production of rabbit polyclonal antibodies and for the development of a routine mass spectrometric technique to detect PAPs. The possible transposition of the previous technique without any a priori to a routine technique using a triple quadrupole was demonstrated by the detection of the 7 peptide markers in PAP samples in only 20 minutes. Porcine MBM and a vegetal feed were contaminated with bovine MBM at 0; 0.1; 0.5; 1; 2; 5 and 10 %. The current limit of detection is 2 % of bovine contamination. A PCA (Principal Component Analysis) statistical approach on these PAP samples was also shown to be powerful, providing a fingerprint of the samples from thousands of MS data, allowing the discrimination between different species, the distinction between a contaminated porcine MBM with 0.1 % of beef and the same uncontaminated MBM, the confirmation of the previously identified peptides markers and the determination of new specific peptides.
These different peptidomics approaches (without any a priori, targeted and statistics) provide answers to the limitations of current methods and could be considered as powerful analytical second-line methods for counter-analyses when there is a doubt on some samples.
Collaborations : CRA-W and CER-Marloie in Belgium and NIFES (Norway)
Funding: Federal Public Service – Health, food chain safety and environment, Brussels (Belgium)