Lors de l'édition 2007 du World Seafood Congress organisé à Dublin du 21 au 25 septembre dernier par l'International Association of Fish Inspectors (IAFI) et le Grimsby Institute for Further and Higher Education, Michel Bakar DIOP a remporté le 3e prix de la compétition de posters scientifiques.

Le travail couronné par la médaille de bronze, intitulé "A Novel Technology for Tropical Fish Preservation by Combined Treatment with Salt and Fermentation Products of Bacteriocin-producing Lactic Acid Bacteria isolated from Traditional Food Products, during storage at 10 °C" est réalisé en alternance au laboratoire du CWBI de la FUSAGx et au Laboratoitre L-MAGI de L’ESP (UCAD, Dakar, Sénégal) dans le cadre des études doctorales de Michel Bakar DIOP.

Michel Bakar DIOP avait obtenu en 2001 une bourse de la CUD pour le cours international en Sciences et Technologie des Aliments. Il poursuit aujourd'hui ses recherches en bénéficiant d'une bourse de doctorat de la CUD dans le cadre du programme Actions-Nord.

Abstract

The search by Developing Countries to ensure the safety and quality of their seafood commodities is became a great challenge, because of importance of microbiological data in food trade system. In this purpose a screening of bacteriocins from Lactic Acid Bacteria isolated from a variety of food products (Maroc, Senegal, and Belgium) was undertaken in the perspective of their application as preservatives in food.

An evaluation of antibacterial activities by combinations of salt with bacteriocins produced by two of these bacteria identified as Lactococcus lactis subsp. lactis (CWBI_B1410), and Lactobacillus curvatus (CWBI_B28), in lean and fat Senegalese fish species (sumpat grunt, giant African threadfin, smoothmouth sea catfish),  purchased from local market, were monitored during 22 days of storage at 10 °C, by total bacteria counts, using a level of 6 log CFU/g as the end of storage, and compared to those of salt with (500 + 500) ppm added sodium benzoate and sorbate.

The level of bacteria in fish species was 5.33 log CFU/g. Enteric and H2S-producing bacteria were dominant during storage of fish at ambient temperatures, whereas lactic acid bacteria became dominant during salt treatment combined with storage at 10 °C. The storage of fish in 14% (m/v) saline solution at 10°C declined of 1.5 log CFU/g the total bacteria counts which were stabilized for 4.5 and 7 days, corresponding to self-life of fat and lean fish species, respectively. The combinations of salt with sodium benzoate and sorbate, cell-free supernatant of CWBI_B1410 cultures, and cell-free supernatant of CWBI_B28 cultures, delayed the increase of bacteria number, resulting an extension of self-life of 14, 12 and 8 days for lean fish, 5, 7 and 8 days for moderately fat fish, and 2.5, 7.5 and 13.5 days for fat fish, respectively.

These data suggest that this soft technology can be a suitable strategy for enhancing bacterial quality of tropical fish products.