Session: Parallel session 10 - Lipidomics, Metabolomics, and Small molecules
Volatolomics based on HS-SPME-GC-Q Exactive-Orbitrap MS to determine volatile organic markers of Listeria monocytogenes
Foodborne pathogens can undergo preventive treatments involving lethal stresses during processing, through cleaning and disinfection procedures for instance. Sometimes, the pathogen can survive. That results in an increased resistance when, further down in the food chain, they encounter stronger lethal stresses. Therefore, studying how pathogens respond to these stresses, is crucial for controlling microbial safety through the food chain.
Hence, the present work aims to assess the relevance of microbial volatolomics (i.e. analysis of volatile organic compounds, VOCs, emitted by microorganisms) in characterizing the response of foodborne pathogen when exposed to an acid stress.
Taking Listeria monocytogenes (L. monocytogenes) as a model pathogen, we determined the most informative bacterial extract for further volatolomics analysis. Based on case-control bacterial cultures, volatolomics was performed by headspace solid phase microextraction (HS-SPME) hyphenated with gas chromatography and high-resolution mass spectrometry (GC-Q Exactive- Orbitrap MS) on three types of sample: (i) the pellet collected after centrifugation which concentrates bacterial cells; (ii) the supernatant which includes what the bacteria released into the growth medium; (iii) the whole culture, which contains global information diluted by the growth medium, but avoids handling of the bacteria samples required by the centrifugation step. The non-targeted analysis of the volatolome of the 3 types of sample using Compound DiscovererTM software shows that pellet, on the one hand, and whole culture and supernatant, on the other hand, provide different and complementary information on the presence of L. monocytogenes. The examination of volatolomics results shows distinctive markers of different acid stress levels applied to L. monocytogenes.
The nature and the origin of the candidate markers was discussed with regard to the literature.
Hence, the present work aims to assess the relevance of microbial volatolomics (i.e. analysis of volatile organic compounds, VOCs, emitted by microorganisms) in characterizing the response of foodborne pathogen when exposed to an acid stress.
Taking Listeria monocytogenes (L. monocytogenes) as a model pathogen, we determined the most informative bacterial extract for further volatolomics analysis. Based on case-control bacterial cultures, volatolomics was performed by headspace solid phase microextraction (HS-SPME) hyphenated with gas chromatography and high-resolution mass spectrometry (GC-Q Exactive- Orbitrap MS) on three types of sample: (i) the pellet collected after centrifugation which concentrates bacterial cells; (ii) the supernatant which includes what the bacteria released into the growth medium; (iii) the whole culture, which contains global information diluted by the growth medium, but avoids handling of the bacteria samples required by the centrifugation step. The non-targeted analysis of the volatolome of the 3 types of sample using Compound DiscovererTM software shows that pellet, on the one hand, and whole culture and supernatant, on the other hand, provide different and complementary information on the presence of L. monocytogenes. The examination of volatolomics results shows distinctive markers of different acid stress levels applied to L. monocytogenes.
The nature and the origin of the candidate markers was discussed with regard to the literature.