PLANTARICIN-D, A BACTERIOCIN PRODUCED BY LACTOBACILLUS-PLANTARUM BFE-905 FROM READY-TO-EAT SALAD

Lactobacillus plantarum BFE 905 isolated from 'Waldorf' salad produced a bacteriocin termed plantaricin D which was active against Lact. sak e and Listeria monocytogenes strains. Plantaricin D was heat stable, r etaining activity after heating at 121 degrees C. The bacteriocin was inactivated by alpha-chymotrypsin, trypsin, pepsin and proteinase K, b ut not by papain and other non-proteolytic enzymes tested. Plantaricin D was stable at pH values ranging from 2.0 to 10.0. The bacteriocin i nhibited growth of L. monocytogenes in automated turbidity assays. Alt hough Lact. plantarum BFE 905 harboured plasmids ranging in size from 3 to 55 kilobase pairs, loss of bacteriocin production could not be co rrelated with plasmid loss. A role for bacteriocin-producing Lact. pla ntarum of vegetable origin in assuring the safety of vegetable foods i s suggested.