Control of the Regrowing Bacteriocin Resistant Variants of Listeria monocytogenes LMG 10470 in vitro and in Food by Nisin-plantaricin UG1 Mixture

Nisin or plantaricin UG1 induced a listericidal action in vitro and in food followed by regrowth of the target cells. The regrowing cells of Listeria monocytogenes LMG10470 were proved to be resistant variants at a resistance frequency from 10-5 to 10-6. The mix of nisin and plantaricin UG1 avoided the regrowth of becteriocin resistant cells of L. monocytogenes LMG10470 in vitro and in food. No cross resistance was found between nisin and plantaricin UG1 as Listerial cells resistant to one bacteriocin were sensitive to the other one; indicating on a synergistic listericidal effect of nisin-plantaricin UG1 mixture which could extend the shelf life of dairy products, meat products and tomato paste.