Partial characterisation of an anti-listeria substance produced by Pediococcus acidilactici P9

To improve the microbiological security of food products, 285 lactic acid bacteria were isolated from koumiss and pickles, and their antimicrobial properties were characterised. Among the strains, Pediococcus acidilactici P9, a strain isolated from a local pickled vegetable, produced an antagonistic substance that inhibited Listeria monocytogenes and Shigella. The substance was heat (121 °C for 20 min) and pH (2.0–10.0) stable, but sensitive to proteolytic enzymes. The production of bacteriocins started at the exponential phase and reached its maximum at the stationary phase, indicating that it was growth related. P. acidilactici P9 also showed an ability to protect HT-29 from invasion by L. monocytogenes and the inhibition rate reached 35.89%. P. acidilactici P9 showed a potential for application in food products as a biopreservative.