ANTIMICROBIAL ACTIVITY OF PROBIOTIC STRAIN Lactobacillus plantarum ISOLATED FROM “SHA’A” AND ASSESSMENT OF ITS VIABILITY IN LOCAL HONEY

Abstract

The acid and bile tolerant strain of Lactobacillus plantarum 2S isolated from sha’a, a maize-based traditionally fermented beverage from Cameroon, was screened for bacteriocin properties and its viability in local pasteurized honey. Bacteriocin activity were checked after their treatment with different enzymes, organic solvents, sodium chloride (NaCl) and detergents as well as their heat stability and effect of pH was studied. This strain produced an antimicrobial substance sensitive to proteolytic enzymes (trypsin and pepsin), thus confirming its proteinaceous nature. pH changes and heat treatment up to 121°C had no effect on the activity of the bacteriocin produced. This bacteriocins inhibited the growth of various indicator organisms with Lactobacillus plantarum 5S having the widest inhibition spectrum. Besides, it showed broad antibacterial activity spectrum against Gram-positive and Gram-negative pathogens including several that are classified as Especially Dangerous Infections by World Health Organization. The mode of action against Lactobacillus plantarum 5S and Salmonella enterica subsp. enterica serovare Typhi ATCC 6539 is bacteriostatic. After 28 days of storage at 4 °C or 25°C, the viable cell numbers of all bacterial strain in both samples were not changed. Lactobacillus plantarum 2S exhibited best viability in honey stored at 4 °C for 28 days and did not altered the physico-chemical characteristics of honey.