Evidence on inhibition of Listeria monocytogenes by divercin V41 action C. Richard, A. Brillet, M.F. Pilet, H. Pre ´vost and D. Drider Laboratoire de Microbiologie Alimentaire et Industrielle, ENTIAA, Rue de la Ge´raudie`re, Nantes cedex, France 2002/365: received 27 November 2002, revised 23 January 2003 and accepted 31 January 2003 ABSTRACT C. RICHARD, A. BRILLET, M.F. PILET, H. PRE ´ VOST AND D. DRIDER. 2003. Aims: The aim of this study was to investigate the role of divercin V41 in inhibition and prevention of Listeria monocytogenes. Methods and Results: Carnobacterium divergens V41 deficient in bacteriocin production was isolated and characterized by enzyme-liked immunosorbent assay, multiplex polymerase chain reaction and bacteriocin diffusion test. Carnobacterium divergens V41 (divercin + ) and Carnobacterium divergens V41C9 (divercin ) ) were grown in the presence of L. monocytogenes in smoked salmon model medium. Carnobacterium divergens V41, but not C. divergens V41C9, was able to inhibit growth of L. monocytogenes. The results indicate that inhibition of L. monocytogenes in the presence of C. divergens V41 is because of the production of divercin V41 and not to a nutritional advantage. Conclusions: Carnobacterium divergens V41 may be a promising agent in food safety. Significance and Impact of the Study: The study demonstrates a potential use of a bacteriocin producing lactic acid bacteria in the area food protection. Keywords: Carnobacterium divergens V41, divercin V41, class IIa bacteriocin, anti-listerial activity, growth inhibition, food-borne pathogen. INTRODUCTION Lactic acid bacteria produce antimicrobial peptides referred to as bacteriocins that have potential as natural food preservatives. Over the last decade, a large variety of bacteriocins have been isolated and characterized allowing to gain insight into the mechanisms involved in self-protection, membrane protein interactions, protein modification, secre- tion and genetic organization (Ennahar et al. 2002). Two main groups of bacteriocins have been established on the basis of their chemical structure (Klaenhammer 1993). The bacteriocins of class I named lantibiotics contain two modified amino acid residues (lanthionine and methyllan- thionine), which are formed post-translationally (De Vos et al. 1995), whereas class II bacteriocins do not contain any post-translational modifications. The class IIa bacteriocins, a subgroup of class II bacteriocins, offer potential industrial applications in the food protection area because of their ability to inhibit the growth of the potentially pathogenic, food-borne Listeria monocytogenes. The class IIa bacteriocins are low-molecular-weight, heat- stable peptides containing at least two cysteine residues in the N-terminal region which form disulphides bridges. The primary structure of class IIa bacteriocins is characterized by the presence of a consensus sequence YGNGVxC(x) 4 V(x) 4 A (x denotes any amino acids) within the conserved N-terminal region, whereas the C-terminal region is more variable with respect to the amino acid sequence. Production of class IIa bacteriocins seems to be affected by environ- mental parameters such as pH (Ahn and Stiles 1990), temperature (De Vuyst et al. 1996), NaCl (Uguen et al. 1999), ethanol (Mortvedt-Abildgaard et al. 1995) and acetate (Nilsson et al. 2002). The class IIa bacteriocin divercin V41 produced by Carnobacterium divergens V41 has previously been isolated Correspondence to: Dr D. Drider, Laboratoire de Microbiologie Alimentaire et Industrielle, ENTIAA, Rue de la Ge ´raudie `re, BP 82225. 44322 Nantes cedex 3, France (e-mail: drider@enitiaa-nantes.fr). ª 2003 The Society for Applied Microbiology Letters in Applied Microbiology 2003, 36, 288–292