Variations in the sensitivity of Listeria monocytogenes types to lactic acid bacteria bacteriocins

Listeria monocytogenes is a cause of human and animal listeriosis, a disease which is often lethal. Food of animal origin is a very important carrier in human infection. This microorganism was found ii, many foodstuffs during the last decode in numerous studies. As a basic precaution for providing consumer food safety investigations are directed toward the greatest reduction of the number of undesirable and pathogenic microorganisms in food. Thus, the sensitivity of Listeria monocytogenes, both clinical/human strains (50) and those found in food of animal origin (48), to lactic acid bacteria bacteriocins was examined at two incubation temperatures (37 degrees C/24h and 4 degrees C/12 days). Namely it is well known that not only closely velated bacterial species, but also less closely velated Gram positive bacteria, may have bactericidal ov bacteriostatics proteins ov protein molecules to L. monocy togeues. Then they can be eventually added to food with the aim of decreasing the risk of listeriosis to the minimum. It was found that bacteriocins, originating from Lactococcus UW and Lactobacillus sake 148 did not expressed inhibitory effects on any of the Listeria strains. However, bacteriocins originating from Lactobacillus sake 265, Pediococcus 347 and Lactobacillus sake 706 had listericidal effects on almost every analyzed type. The highest bactericidal effect was expressed by bacteriocins from Lactobacillus sake 265. There was statistically a very significant difference (p < 0.01) and a significant difference (p < 0.05) between the arithmetic mean values for inhibition zones with clinical/human strains and those originating from foodstuffs. II was found that the incubation time and temperature influenced the inhibitory effects of bacteriocins, too.