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Fluorescence-Based Comparative Evaluation of Bactericidal Potency and Food Application Potential of Anti-listerial Bacteriocin Produced by Lactic Acid Bacteria Isolated from Indigenous Samples
- Singh, Atul Kumar, Mukherjee, Sandipan, Adhikari, Manab Deb, Ramesh, Aiyagari
- Probiotics and antimicrobial proteins 2012 v.4 no.2 pp. 122-132
- Bacillus cereus, Enterococcus faecalis, Lactobacillus plantarum, Lactococcus, Listeria monocytogenes, Pediococcus, Staphylococcus aureus, antibacterial properties, cucumbers, culture filtrates, dried fish, fermented foods, genes, lactic acid bacteria, paneer, plantaricins, polymerase chain reaction
- The aim of the present study was to ascertain the potency of anti-listerial bacteriocin produced by lactic acid bacteria (LAB) isolated from indigenous samples of dahi, dried fish, and salt-fermented cucumber. A total of 231 LAB isolates were obtained from the samples, of which 51 isolates displayed anti-listerial activity. The anti-listerial LAB were identified by PCR as Lactobacillus sp., Pediococcus sp., Enterococcus sp., and Lactococcus sp. PCR also enabled the detection of Class IIa bacteriocin-encoding genes such as enterocin A, pediocin, and plantaricin A in some of the LAB isolates. The culture filtrate from anti-listerial LAB isolates demonstrated bacteriocin-like inhibitory substance (BLIS) against common Gram-positive pathogenic bacteria such as Staphylococcus aureus, Enterococcus faecalis, and Bacillus cereus, and partial characterization of BLIS confirmed the production of bacteriocin by the LAB isolates. Sensitive fluorescence-based assays employing specific probes indicated the comparative potencies of the bacteriocin and clearly revealed the membrane-targeted anti-listerial activity of the purified bacteriocin produced by selected LAB isolates. The food application potential of plantaricin A produced by a native isolate Lactobacillus plantarum CRA52 was evidenced as the bacteriocin suppressed the growth of Listeria monocytogenes Scott A inoculated in paneer samples that were stored at 8Â Â°C for 5Â days.