Abstract: In this study, headspace-solid phase micro-extraction followed by gas chromatography-mass spectrometry (HS-SPME/GC-MS) was employed to detect the volatile metabolites of Staphylococcus aureus. The specificity, stability and practical application of 3-methyl-butanal and 3-methyl-butyric acid as candidate metabolite markers to detect S. aureus were investigated. The results showed that S. aureus produced 3-methyl-butyric acid as its specific metabolite but not 3-methyl-butanal when cultured in 7.5% NaCl broth. The release of 3-methyl-butyric acid was not affected either by different S. aureus strains or by Escherichia coli O157:H7 and/or Salmonella enteritidis co-cultured with S. aureus indicating good stability. For raw pork, raw milk and cooked rice samples, the volatile metabolite markers-based method was highly consistent with the traditional culture method and the PCR assay. The method proposed in this study was simple to operate and could be expected to be a promising candidate for the detection of viable S. aureus.

Key words: Staphylococcus aureus; volatile metabolites; detection markers; headspace-solid phase micro-extraction followed by gas chromatography-mass spectrometry