Bacteriocins from lactic acid bacteria are considered as safe additives to control the frequent development of pathogens and spoiling microbes in food and feed. The present study deals with the screening of three standard strains of lactobacilli like Lactobacillus casei(NCIM No. 2732), Lactobacillus fermentum(NCIM No. 2166) and Lactobacillus plantarum(NCIM No. 2373) for bacteriocin production. The antibacterial activity was analyzed against two food borne pathogens, E.coliand Pseudomonas aeruginosa. Among the three strains, L.caseiwas found to be the most potent based on the zones of inhibition recorded against both the test organisms. The L.caseibacteriocin was partially purified by ammonium sulphate precipitation. Physico-chemical characterization of the partially purified bacteriocin revealed that the compound was relatively stable up to 700C for 30 min. Further heat treatment led to complete loss of activity. The pH stability studies of bacteriocin showed that there was a significant increase in the antibacterial activity from a pH of 3-7; no activity was recorded beyond pH 11. Evaluation of antibacterial activity at different storage periods at 40C revealed that up to 7 days the activity was stable and thereafter there was a gradual decrease in the activity. The proteinaceous nature of bacteriocin was confirmed by treatment with trypsin.