Antagonistic effect of coryneform bacteria from red smear cheese against Listeria species.

A total of 187 coryneform bacteria were isolated from red smear and screened for inhibitory effects against 16 strains of Listeria species. Culture filtrates from Brevibacterium linens (16 strains), Arthrobacter nicotianae (4 strains) and Arthrobacter nucleogenes (3 strains) showed clear zones of inhibition. The antagonistic effect was seen against 26 to 87% of 91 Listeria strains tested. A. nicotianae and A. nucleogenes were more effective against Listeria innocua and Listeria ivanovii than against Listeria monocytogenes. No species specifically was observed for B. linens, but there was a difference regarding the inhibitory activity of individual culture filtrates. When culture filtrates of the test strains were added to Listeria broth cultures, the maximum growth level was not attained. Inhibition in broth cultures was dependent on the concentration of culture filtrates. Culture filtrates from the late stationary phase had a stronger inhibitory effect on the growth of L. monocytogenes. The nature of the inhibitory effects remained unclear. Attempts to characterize the nature of the antagonism showed that the culture filtrates lost their inhibitory activity upon heating, and the molecular size of the inhibitory substances were greater than 12-14 kDa.