Enterobacteria and lactic acid bacteria fight during spontaneous vegetable fermentation - Archive ouverte HAL Accéder directement au contenu
Communication Dans Un Congrès Année : 2022

Enterobacteria and lactic acid bacteria fight during spontaneous vegetable fermentation

Résumé

Introduction and objectives Fermented vegetables are traditionally consumed in central Europe and Asia, and have recently received a renewed interest in Western Europe, leading to their domestic and artisanal production. Our objective was to better understand the microbial dynamics of such spontaneous fermentations and the potential safety risks associated with their consumption. Materials and et methods A 23 experimental design was set up for two vegetables, cabbage and carrots, either coarsely or finely cut, firmly pressed down in 500 mL-jars and filled up with brine to reach final NaCl concentrations of 0.8% or 1.0% (w/w). Jars were incubated at 19°C for 7 months and two independent jars characterized at each time point using culture-dependent and -independent (16S metabarcoding) approaches. 1 to 5 isolates picked up from plates were identified by 16S sequencing. pH and pathogenic bacteria were also analysed. Results, discussion and conclusion The types of vegetables and of cutting significantly influenced microbial counts and pH, while the NaCl concentration did not. In both sliced and grated carrots, the pH rapidly dropped to < 3.9, while lactic acid bacteria (LAB) counts ranged from 7.7 to 9.1 log CFU/g-1 and enterobacteria from 6.1 to 7.2 log after 40 h. In contrast, lactic fermentation was far slower in grated and leaf cabbages. After 40 h, their pH was still > 6.1 and enterobacteria counts (> 8 log) exceeded LAB counts (0 to 5.8 log). A great variability was observed from replicate jars especially for leaf cabbage. Yeasts were systematically detected at the beginning of fermentation. After 7 months, all vegetables were at pH < 3.7 and enterobacteria no more detected. No pathogenic bacteria were detected. On the 59 clones isolated from MRS plates, 16 taxons were identified, including mainly Leuconostoc, followed by Lactobacillus-related species, in both vegetables. Metabarcoding analysis strongly differentiated the two vegetables, with around 70% of shared ASV between carrot and cabbage, and their cutting, in particular for cabbage leaf. This study highlights the tight competition between enterobacteria and LAB in the colonisation of fermented vegetables, illustrates the diversity of their microbiota, and highlights a great variability between replicate jars.
Fichier non déposé

Dates et versions

hal-03805173 , version 1 (07-10-2022)

Licence

Paternité - Pas d'utilisation commerciale - Pas de modification

Identifiants

  • HAL Id : hal-03805173 , version 1

Citer

Anne Thierry, Marie Noëlle Madec, Anne-Sophie Bage, Victoria Chuat, Laurent Marché, et al.. Enterobacteria and lactic acid bacteria fight during spontaneous vegetable fermentation. 17e congrès national de la SFM « La microbiologie dans tous ses états », Société Française de Microbiologie, Oct 2022, Montpellier, France. ⟨hal-03805173⟩
33 Consultations
0 Téléchargements

Partager

Gmail Facebook X LinkedIn More