Fatty acid profile and bio-preservative efficacy of lactic acid bacteria postbiotics for improving microbiological safety in broiler meat

Abstract

Postbiotics derived from lactic acid bacteria (LAB) are promising natural antimicrobials due to their bioactive metabolites. This study evaluated their chemical composition and antimicrobial efficacy both in vitro and in vacuum-packaged broiler breast meat inoculated with meatborne pathogens during 10 days of storage. Postbiotics from Lactiplantibacillus plantarum (LP), Lactobacillus acidophilus (LA), and Lacticaseibacillus rhamnosus GG (LGG) were prepared by culturing LAB in MRS broth, followed by centrifugation and filtration, and subjected to GC-MS analysis. Neutralized postbiotics were used to obtain bacteriocin-like substances (BLS). Both postbiotics and BLS were tested against Escherichia coli, Salmonella Typhimurium, Staphylococcus aureus, and Bacillus cereus in an in vitro assay, while postbiotics were applied to the meat in a 1:5 ratio in the meat model. Principal component analysis demonstrated distinct strain-specific fatty acid profiles, with oleic acid driving separation among LAB-postbiotics. In vitro, BLS achieved peak inhibition within 4–12 h, reducing OD600nm of E. coli and Salm. Typhimurium by 40–50 % at 12 h, whereas postbiotics provided stronger early suppression, lowering these pathogens by 80–86 %, with the highest activity by LGG-postbiotics (86 %). In the model, untreated samples exhibited an increase in total mesophilic aerobic bacteria, Gram-negative, and Gram-positive pathogens from 6.91 to 9.26 log10 CFU/g, whereas postbiotic treatments reduced counts to 1.06–3.64, 1.41–4.36, and 0.93–3.30 log10 CFU/g, respectively, with higher concentrations more effective. LGG-postbiotics reduced Salm. Typhimurium in broiler meat compared to LA and LP. In conclusion, LAB-derived postbiotics, particularly LGG, could be used as natural preservative agents to improve microbiological safety in the broiler industry