vegetables Lactic acid bacteria (LAB) have vital roles in plant food safety, quality, and health promotion. Despite their recognized importance in the production of fermented fruits and vegetables, the prevalence, abundance, and diversity of LAB on those plant foods pre- and post-harvest are not well understood. Our studies have shown that LAB populations on (fermented) fruits and vegetables fluctuate from levels that are below detection to over 10^7 cells per gram tissue and are influenced by environmental conditions, plant species, and microbial succession dynamics. Besides the known, species-level differences among LAB genera, characterization of a collection of 13 strains of Lactiplantibacillus plantarum (a LAB formerly known as Lactobacillus plantarum) from fresh and fermented plant food sources revealed high levels of intraspecific diversity. L. plantarum strains were highly variable with regard to genome content (genome size, enzymatic pathways), the capacity to grow on different carbohydrates (mono- and poly-saccharides), tolerate environmental stresses (high temperature, low water activity, acidic pH, and high alcohol content), form biofilms, and inhibit yeast growth. This variation was associated with the source from which the strain was isolated, indicating that L. plantarum is adapted at the strain level for specific (fermented) plant foods. Furthermore, examination of multiple L. plantarum strains isolated from the same fermented plant food samples showed that these bacteria have evolved for intraspecies co-existence in food fermentations through gene loss and niche differentiation. The findings provide opportunities to use LAB strain-specific approaches to maximize health and sensory aspects of fruits and vegetables.

Distribution and intraspecific diversity of lactic acid bacteria in fresh and fermented fruits and vegetables

ACS Spring Meeting 2021

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.