Microbial volatolomics by SPME-GC-HRMS for phenotyping Listeria monocytogenes response to acid stress
Year: 2024
Type: conference-paper
Abstract: 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 robustness (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 aim of the present work was 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 implemented a two-step strategy.The first step aimed to determine the most informative bacterial extract for further volatolomics. Based on case-control experiments (cultures on synthetic growth medium with/without L. monocytogenes), volatolomics was performed by headspace solid phase microextraction (HS-SPME) hyphenated with gas chromatography and high-resolution mass spectrometry (GC-Q Exactive-HRMS Orbitrap®) on three types of samples: (i) the pellet collected after centrifugation of the whole culture which concentrates bacterial cells; (ii) the supernatant collected after centrifugation of the whole culture, 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 Discoverer® 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 in the culture medium. Based on the results of the first step, the response of L. monocytogenes to acid stress was secondly studied through volatolomics analysis of pellet and whole culture samples, collected after bacterial culture. The examination of volatolomics results shows distinct markers of different acid stress levels applied to L. monocytogenes. The discussion will focus on the origin of these markers with regard to the literature and on the perspectives of this volatolomics study
Source: HAL
Authors: Fakih, Aya, ratel, jérémy, Mercier, Frédéric, Kondjoyan, Nathalie, Tsoureki, Dimitra, Botta, Cristian, Rantsiou, Kalliopi, Engel, Erwan
Institutions: Qualité des Produits Animaux, University of Turin
Language: English
Subfield: Biotechnology
Domain: Life Sciences
Open Access status: green
OpenAlex ID: W4407267150