Evaluation and verification of the characteristic peptides for detection of Staphylococcus aureus in food by targeted LC-MS/MS

The traditional methods for detection of Staphylococcus aureus in food have some shortcomings, such as fussy operation and dependence on separation of pure colony. A novel strategy for detection of pathogenic bacteria bases on targeted analysis of the characteristic peptides by LC-MS/MS. The key to the success of this strategy is to identify a combination of reliable characteristic peptides that afford high specificity. In this study, the candidate characteristic peptides of S. aureus were evaluated bioformatically and then verified experimentally. UniProt protein database were used to perform BLAST analysis on the candidate characteristic peptides, and then their specificity were compared via targeted analysis in S. aureus and other Staphylococcus strains by LC-MS/MS. Finally, suitable S. aureus characteristic peptide was determined, by using which 100 cfu/mL S. aureus in milk samples were successfully detected, meeting the detection limit requirement in actual application. The results demonstrated the feasibility of the detection strategy of S. aureus based on characteristic peptides. The explor-atory work is expected to promote the methodology research of food-borne pathogen inspection and further improve the inspection efficiency and quality.