The objective of this study was to develop an appropriate method for detecting specific bacteriocin-mediated inhibition. This method could be used to determine the effectiveness of known bacteriocin-producing lactic acid bacteria against foodborne pathogens. Lactococcus lactis subsp. lactis 11454, Pediococcus pentosaceous FBB61, and P. pentosaceous FBB63-DG2 were evaluated for their ability to inhibit a variety a foodborne pathogens. Of the three procedures used, the agar spot method was chosen as the most reproducible and reliable assay method. After optimization of the plate agar media composition, and the time and temperature of the assay, the three bacteriocin-producing strains were screened against a broad range of Gram-positive and Gram-negative foodborne pathogens. The three bacteriocin-producing organisms inhibited the following Gram-positive foodborne pathogens: Bacillus cereus, Clostridium perfringens. Staphylococcus aureus, and 22 representatives of 5 species of Listeria including L. monocytogenes, L. ivanovii, L. innocua, L. seeligeri, and L. welshimeri. Additionally, strain 11454 slightly inhibited several Gram-negative foodborne pathogens, including Aeromonas hydrophila AH2, Escherichia coli 0157:H7, Vibrio cholerae 851, and V. parahaemolyticus A865957. Gram-negative organisms not inhibited by any of the bacteriocin-producing organisms included Campylobacter jejuni, several serovars of Salmonella enteriditis, and species of Yersinia and Vibrio.

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Author notes

1Published as paper No. 17.081 of the contribution series of the Minnesota Agricultural Experiment Station.