10.22376/ijpbs.2019.10.1.p1-12 Volume 8 Issue 4 2017 (October - December) Bacteriocins from bacteria inhibit the growth of similar or closely related bacterial strains. Present investigation was focused on to check the antibacterial activity of bacteriocin produced from lessThan i greaterThan Lactobacillus lessThan /i greaterThan and lessThan i greaterThan Lactococcus lessThan /i greaterThan bacteria against various pathogens of food spoilage and bovine mastitis. A total of 62 (15.93%) lessThan i greaterThan Lactobacillus lessThan /i greaterThan and 22 (5.65%) lessThan i greaterThan Lactococcus lessThan /i greaterThan isolates were tentatively identified from 389 commercial food products by using morphological, biochemical and molecular characterization. All the isolates were further confirmed has lessThan i greaterThan L. plantarum lessThan /i greaterThan [22 (5.65%)] and lessThan i greaterThan L. acidophilus lessThan /i greaterThan [18 (4.62%)] and lessThan i greaterThan Lactococcus lactis lessThan /i greaterThan [22 (5.65%)] by polymerase chain reaction. In PCR, lessThan i greaterThan recA lessThan /i greaterThan gene (318bp) and 16s-23s rRNA interspecific spacer regions (575bp) were amplified from the isolates of lessThan i greaterThan L. plantarum lessThan /i greaterThan and lessThan i greaterThan L. acidophilus lessThan /i greaterThan respectively, whereas, lessThan i greaterThan gad lessThan /i greaterThan B lessThan i greaterThan lessThan /i greaterThan (602bp) gene was amplified from lessThan i greaterThan Lactococcus lactis lessThan /i greaterThan . The optimal conditions for the extraction and partial purification of bacteriocin were standardized by using ammonium sulphate precipitation and sephadex column chromatography respectively. Bactericidal activity of all bacteriocin producing lessThan i greaterThan Lactobacillus lessThan /i greaterThan and lessThan i greaterThan Lactococcus lessThan /i greaterThan isolates lessThan i greaterThan lessThan /i greaterThan were tested against six major indicator bacteria of food spoilage and bovine mastitis like lessThan i greaterThan Listeria monocytogenes, Escherichia coli, Salmonella enterica lessThan /i greaterThan Typhimurium lessThan i greaterThan , Staphylococcus aureus, Streptococcus agalactiae lessThan /i greaterThan and lessThan i greaterThan Staphylococcus epidermis lessThan /i greaterThan . The crude bacteriocin produced anaerobically by lessThan i greaterThan L. acidophilus lessThan /i greaterThan isolates after 96hrs of incubation at 37°C showed higher antibacterial activity than lessThan i greaterThan L. plantarum lessThan /i greaterThan and lessThan i greaterThan Lactococcus lactis lessThan /i greaterThan . The purified bacteriocin showed significantly increase in the zone of inhibition against lessThan i greaterThan Staphylococcus lessThan /i greaterThan lessThan i greaterThan aureus lessThan /i greaterThan and lessThan i greaterThan Streptococcus lessThan /i greaterThan lessThan i greaterThan agalactiae lessThan /i greaterThan than other bacteria. Present investigation suggested that the PCR is a simple, rapid and reliable method of diagnosis of lessThan i greaterThan Lactobacillus lessThan /i greaterThan and lessThan i greaterThan Lactococcus lessThan /i greaterThan bacteria up to species level. The purified bacteriocin produced from lessThan i greaterThan L. acidophilus lessThan /i greaterThan was found to have inhibitory action against the Gram positive and Gram negative pathogens in foodborne and bovine mastitis . ARUNAVA DAS , M. E. SINDUJA, K. HARSHADHA, J. BINDHU, R. BALAKRISHNARAJA Lactobacillus acidophilus, Lactococcus lactis, Lactobacillus plantarum, Bacteriocin, Polymerase chain reaction. 432-439