Influence of enterococci and lactobacilli on listeria

Abstract

A collection of lactic acid bacteria (38 Enterococcus and 41 Lactobacillus strains) was tested for the antilisterial activity against 15 Listeria spp. strains (two L. monocytogenes, one L. ivanovii and 12 L. innocua strains) using agar spot method. Out of all 79 bacteria only six Enterococcus strains (1/3A, 3/3A, 6/4D, 6/1A, 1282 and EN3) exhibited antilisterial activity against almost all used indicator strains, when their live cells were tested. When their cell free neutralised supernatants (CFNS) were tested against four selected indicator strains (L. innocua Ln-03, Ln-06, Ln-10 and L. monocytogenes CCM5576) only two Enterococcus spp. strains were active - E. faecalis 6/1A strain from raw cow milk of minor interest due to the activity of its CFNS only against L. innocua Ln-06 and thermolability of the compound and E. mundtii 1282 strain from goat raw milk with CFNS active against 13 Listeria spp. strains including L. monocytogenes. E. mundtii 1282 strain produced probably a bacteriocin, because it completely lost the activity after treatment CFNS with proteinase K.