Characterization and application of postbiotics of Lactobacillus spp. on Listeria monocytogenes in vitro and in food models

Abstract

Anti-listeria and functional characteristics of postbiotics (metabolic byproducts of probiotics) of Lactobacillus acidophilus LA5 and L. casei 431 and L. salivarius were investigated in vitro, and in ground meat and whole milk. Antibacterial activity of all examined postbiotics was mainly associated to pyrrolo [1,2-a] pyrazine-1,4-dione and somewhat to the presence of different organic acids. Postbiotics of all Lactobacillus spp. maintained their residual antimicrobial activity over 50% at different pH levels (4, 5, 6, 7, 8 and 9). Postbiotics also exhibited a biofilm removal activity on L. monocytogenes, this activity depended on the type of postbiotics and the contact time. Lower minimum effective concentration (MEC) of postbiotics were varied in food models and remarkably, a low MEC index (15 mg/mL) was observed for postbiotics of L. salivarius. The postbiotics prepared from lactobacillus spp. especially L. salivarius has an applicable functional property in vitro and in food models.