Microorganisms Isolated from Stored Meat in India, with Potential Antimicrobial Activity against Food Pathogens

Background: World Health Organization has estimated that 1 in 10 people fall ill and 4, 20, 000 die every year from eating contaminated food. Food pathogens like Escherichia, Salmonella, Staphylococcus and Listeria pose a serious threat to human health. Objective: The objective was to isolate microbes from meat stored at refrigerated conditions and evaluate the antimicrobial activity of the cell-free supernatant against food pathogens. Methods: Chicken and Pork samples were procured and stored at refrigerated conditions (4-7ºC) for 2 weeks. The samples were plated on to Nutrient agar (NA) and De Man, Rogosa and Sharpe (MRS) agar for isolation of aerobic and lactic acid bacteria. Cell-free supernatants of the isolates were screened for antimicrobial activity against Escherichia coli, Salmonella typhimurium, Listeria monocytogenes and Staphylococcus aureus by microtiter plate assay. The 5 most - effective strains were screened for hemolytic activity and identified by 16s rRNA sequencing. Results: A total of 110 strains were isolated, out of which the top 5 most - effective strains were all from MRS agar. They showed 88-90% inhibition against E. coli and S. typhimurium, whereas 60 to 70 % against S. aureus and L. monocytogenes. These strains were found to be non - hemolytic and were identified as Leuconostoc spp. namely, L. mesenteroides subsp. mesenteroides J18, CP003101; L. mesenteroides LM2; L. mesenteroides ATCC 8293, CP000414; L. gelidum subsp. gasicomitatum LM G 18811 and L. mesenteroides; LM2, AY675249. Conclusion: Leuconostoc are known to be effective in controlling foodborne pathogens and therefore, these strains have the potential for application in food and human.