Antilisterial activity of carnocin 54, a bacteriocin from Leuconostoc carnosum

Abstract

Carnocin 54, a bacteriocin produced by Leuconostoc carnosum LA54A acts very rapidly in a bactericidal manner on Listeria cells. The killing kinetics strongly depend on bacteriocin concentration and pH. At a high concentration, more than 99·99% of the cells were killed within 1 min. Lowering carnocin concentration and increasing pH from 4·9 to 6·5 resulted in a slower reduction of Listeria viable counts. Carnocin was able to inactivate Listeria cells to the same extent at pH 4·5 and 6·5 within 5 h. After 24 h, however, a slight resurgence of Listeria was observed at pH 6·5. The bactericidal efficiency was Listeria strain dependent, but was not influenced by the growth phase. At a given bacteriocin concentration, the level of inactivation of Listeria was not affected by the initial cell number.