Bacteriocins From Lactobacillus Strains and Their Anti-Listeria Monocytogenes in Nham, Thai Fermented Pork

In this study, two bacteriocin-producing Lactobacillus strains (the isolates LS0602 and LT0904) isolated from Thai fermented pork products were identified by 16S rDNA sequence analysis. The isolate LS0602 was found to be Lactobacillus plantarum, whereas the isolate LT0904 was Lactobacillus brevis. Their bacteriocins were partially purified by ammonium sulfate precipitation, dialysis and trichloroacetic acid precipitation. Bacteriocin activity was determined by agar well diffusion assay and critical dilution method against Listeria monocytogenes. The partial purified bacteriocins from L. plantarum LS0602 and L. brevis LT0904 had strong inhibitory activity against the growth of L. monocytogenes at 819,200 AU/ml and 409,600 AU/ml, respectively. These bacteriocins were used to control the growth of L. monocytogenes in Nham during fermentation at 30°C. The partial purified bacteriocins (4%) in combination with L. plantarum LS0602 starter culture could reduce the number of total presumptive Listeria counts in Nham by 1.5 log unit after 3-day fermentation.

Keywords: Lactic acid bacteria, bacteriocins, fermented meat, starter culture

^*Corresponding author: snanasombat@gmail.com