Characterization of anti-listerial bacteriocin produced by lactic acid bacteria isolated from traditional fermented foods from Cambodia

Listeria monocytogenes is a foodborne pathogen associated with fermented products. The aim of this study was to characterize anti-listerial bacteriocin produced by lactic acid bacteria (LAB) isolated from Cambodian fermented foods. Four LAB isolates of confirmed bacteriocin production were isolated from fermented fish and shrimp (pha ak trey, pha ak kampus). These isolates demonstrated antimicrobial activity against Listeria monocytogenes NCTC 11994 and were identified as Pediococcus pentosaceus by 16S rRNA analysis. Based on these results, one isolate was selected (P. pentosaceus CFF4) and its bacteriocin was characterized. Complete inactivation or significant reduction in bacteriocinogenic activity was observed after treatment with proteases and a -amylase, suggesting that the bacteriocin besides the proteinaceous nature has the presence of a glycosidic moiety that may be required for its activity. The molecular weight of the bacteriocin was approximately 3.5 kDa, as determined by tricine-SDS-PAGE. The bacteriocin activity was unaltered for pH values ranging from 2 and 10, and temperatures between 4 and 60°C. Pediococcus pentosaceus CFF4 could be considered for use as a starter culture producing anti-listerial agents in fermented foods. Further studies are still needed concerning the biopreservative properties of the purified bacteriocin and the organoleptic characteristics of the foods.