Recently our research has allowed developing and using a novel electro-transformed strain of Lactobacillus LMG21688 as protective cultures for inhibiting Listeria monocytogenes in meat products. The result did not give total satisfaction because of the complexity of the matrix (meat) used. To show the total efficiency of this new strain against Listeria, another matrix less complex was tested. Different types of milk (full-cream and skimmed) were used in laboratory fermentations where Listeria monocytogenes was co-cultured at 37°C with either electrocompetent LMG21688 or Lactobacillus curvatus CWBI-B28 bacteriocin-producing strain. The Listeria cfu count reached after 168 hours was 200 times higher in high-fat milk than in skimmed milk.