Abstract

The present study was undertaken to assess the inhibitory potential of lactic acid bacteria isolated from traditionally processed corn-beer and palm-wine on Escherichia coli, Salmonella typhi and Staphylococcus aureus. Lactic acid bacteria were isolated on MRS agar using pour plate method. The catalase negative and Gram positive isolates were selected as presumptive lactic acid bacteria and were biochemically characterized using the API 50 CHL BioMerieux kit to identify them at species level. The LAB isolates were then assessed for antimicrobial activity potentials against food-borne pathogens. Thirteen LAB isolates which constituted nine different species namely: Lactobacillus fermentum, Lactobacillus plantarum, Lactobacillus brevis, Lactobacillus acidophilus, Lactobacillus bulgaricus, Leuconostoc mesenteroides, Leuconostoc carnosum, Pedioccocus acidilactici and Lactobacillus pentosus were isolated from these two beverages. The entire LAB isolates demonstrated great potentials to inhibit the test pathogens. P. acidilactici from corn-beer exhibited the overall highest inhibitory activity with zones of inhibition of 19, 20 and 16 mm on E. coli, S. typhi and S. aureus, respectively; while the isolate from palm-wine, L. pentosus exerted the highest antimicrobial action on the test pathogens. It was observed that most of the LAB isolates inhibited the indicator pathogens mainly by bacteriocin production. S. typhi was the most susceptible food-borne bacterial pathogen to the inhibitory activity of the LAB isolates, followed by E. coli.

Key words: Lactic acid bacteria, food-borne pathogens, antimicrobial activity, probiotics, bacteriocins.