Bacteriocinogenic activity of lactobacilli from fermented sausages

During the screening of the inhibitory activity of 254 strains of lactobacilli isolated from fermented sausages at different times of ripening, 22% of the strains showed inhibition that was not related to acid or hydrogen peroxide, towards one or more indicator strains. Not all the strains were capable of secreting the inhibitory compound in the supernatant fluid. The characterization of the inhibitory compound from three strains showed that they were bacteriocins with a bactericidal mode of action and a molecular weight exceeding 10,000 Da. Lactobacillus plantarum CTC 305, CTC 306 and Lact. sake CTC 372 inhibited Listeria monocytogenes. Lactobacillus sake CTC 372 was cured of two plasmids of 84.8 kbp and 41.3 kbp, losing the production and the immunity of a bacteriocin as well as the ability to ferment lactose.