Production of biogenic amines and divercin V41 in cold smoked salmon inoculated with Carnobacterium divergens V41, and speci®c detection of this strain by multiplex-PCR N. Connil, H. Pre Âvost and X. Dousset Laboratoire de Microbiologie Alimentaire et Industrielle, ENITIAA, Nantes, France 2001/143: received 16 June 2001, revised 1 October 2001 and accepted 16 October 2001 N. CONNIL, H. PRE Â VOST AND X. DOUSSET. 2002. Aims: The objective of this study was to determine the technological behaviour (implantation and biogenic amines production) of Carnobacterium divergens V41, an anti-Listeria bacteriocin producer (divercin V41), after inoculation in cold smoked salmon (CSS). Methods and Results: Implantation of the strain was followed by multiplex-PCR during 27 days of storage at 4°C, and biogenic amines were quanti®ed by HPLC. It was found that the strain was able to develop quite well in CSS among lactic wild ¯ora. Divercin V41 (400 AU ml )1 ) was produced in CSS, and the biogenic amine content was not modi®ed by inoculation of the bacteria. Conclusions: Carnobacterium divergens V41 is a safe, interesting, bioprotective agent. Signi®cance and Impact of the Study: This strain could potentially be used for ef®cient prevention of L. monocytogenes growth in CSS. INTRODUCTION The production of organic acids and bacteriocins by lactic acid bacteria makes them competitive against other bacteria, including some pathogens such as Listeria monocytogenes. Furthermore, most lactic acid bacteria producing bacteriocins are able to grow at low temperature, so they could potentially be used to extend ef®ciently the shelf-life of refrigerated products such as cold smoked salmon (CSS). There has been some interest in the development of a biopreservation process for CSS because this ready-to-eat seafood may be contaminated by L. monocytogenes (Jemmi 1993). Food biopreservation processes using lactic acid bacteria have already been proposed, mainly for meat (Schillinger et al. 1991; McMullen and Stiles 1996) and, to a less extent, for ®sh products (Jeppesen and Huss 1993; Nilsson et al. 1999). To date, nisin (NisaplinÒ) is the only bacteriocin approved by FDA as a food additive. It is used in processed cheese products, milk and dairy products, canned vegetables, soups and fruit juices, but not in ®sh. A biopreservative process for CSS would need to check the effective production and activity of the bacteriocin in this food matrix, as well as the safety of the strain. Divercin V41, the class IIa bacteriocin produced by Carnobacterium divergens V41 isolated from trout (Pilet et al. 1995), has been chemically and genetically characterized (Metivier et al. 1998; Bhugaloo-vial et al. 1999). This bacteriocin, due to its high inhibition activity against L. monocytogenes (Guyonnet et al. 2000), has potential for eventual use in biopreservation of CSS. A previous physiological study showed that addition of divercin V41, or the bacteriocin producer strain C. divergens V41, to sterile CSS inoculated with L. monocytogenes could signi®cantly reduce the growth of the pathogen (Duffes et al. 1999). Indeed, these authors observed that the preservative ef®cacy of the strain C. divergens V41 in cold smoked salmon was about 1 log reduction of L. monocytogenes growth at 4°C, and about 5 log at 8°C after 21 days of storage. Nevertheless, Carnobacterium strains can produce biogenic amines (Masson et al. 1996), especially tyramine, and it is well documented that biogenic amines can have toxicological effects (ten Brink et al. 1990; Silla Santos 1996). Therefore, to ensure that C. divergens V41 would be a safe candidate for potential biopreservation, its biogenic amines and divercin V41 production in CSS during 27 days of storage at 4°C were studied. Furthermore, as the competitiveness of C. divergens V41 among the indigenous lactic ¯ora of CSS was unknown, a multiplex- PCR technique was developed that enabled fast and speci®c detection of the strain C. divergens V41 in CSS. Correspondence to: X. Dousset, Laboratoire de Microbiologie Alimentaire et Industrielle, ENITIAA, rue de la GeÂraudieÂre, BP82225, 44322 Nantes Cedex 03, France (e-mail: dousset@enitiaa-nantes.fr). ã 2002 The Society for Applied Microbiology Journal of Applied Microbiology 2002, 92, 611±617