Sensitivity variations of Listeria strains to the bacteriocins, lactocin 705, enterocin CRL35 and nisin

Five strains of Listeria monocytogenes, four strains of Listeria innocua an d a strain of Listeria seeligeri showed different sensitivities to lactocin 705 (17 000 AU ml(-1)), enterocin CRL35 (8500 AU ml(-1)) and nisin (2500 I U ml(-1)) at different pHs (5, 6 and 7). The susceptibility of Listeria str ains to bacteriocins at each pH was strain dependent, and it was enhanced a t the low pH. L. monocytogenes had enhanced nisin tolerance while the non-n isin bacteriocins were more inhibitory with viability losses of 3-3.4 in co ntrast with 1.5-1.8 log cycles, respectively. Lower viability loss values w ere obtained with L. innocua strains with all three bacteriocins while L. s eeligeri was more sensitive to nisin than to lactocin 705 or enterocin CRL3 5.