Author(s): P. Venkatachalamâ°,D.Daniel Selvakumarand J. Muthukumar
In this study extractsofLactobacillus caseiand Ocimum sanctumwere separated and analysed for their antibacterial activity against the food borne human pathogenListeria monocytogenes. Lactobacillus caseiand Listeria monocytogeneswereisolated from milk sample.The bacterial culture of Lactobacillus caseiwas inoculated in nutrient broth and incubated for 24 hours and 7 days on rotary shaker at 28±2oCto obtain their antilisterial compounds.The petroleum ether extractsofLactobacillus caseiand Ocimum sanctumwere analyzed for their antagonisticproperties against Listeria monocytogenes.Their inhibitory patterns were measured in both individual and dual extracts.The petroleum ether extract of Lactobacillus caseiculture broth showed good inhibitory result against Listeria monocytogeneswhen compared with Ocimum sanctumextract.Lactobacillus caseiproduced 54mm zone of inhibition on the growth of Listeria monocytogenesat a concentration of 150μl. Ocimum sanctumproduced 46mm zone of inhibition on the Listeria monocytogenes at a concentration of 200 μl. Dual extract of petroleum ether of Ocimum sanctum extract and Lactobacillus caseiextract (1:1 ratio) produced 40mm zone of inhibition on the Listeria monocytogenes at a concentration of 200 μl.GC-MS analysis revealed the various components present in the Lactobacillus caseiand Ocimum sanctumextracts.