Protective Bacteria: An Option to Control Listeria monocytogenes in Seafood Products

Listeria monocytogenes is responsible of human listeriosis, a severe foodborne disease (1,763 human cases in Europe in 2013, 15.6% fatality rate ⁽¹⁾). Among ready to-eat-food products, seafood and fishery products usually show the highest level of non-compliance (presence in 25g) according to the European microbiological criteria ⁽¹⁾. A wide range of seafood products such as sushi, fish carpaccio, smoked or marinated fish, cooked shrimp are considered as low preserved since they can be consumed raw or after salting, cold smoking or mild cooking. During cold storage of these foodstuffs, usual preservative methods are vacuum or modified atmosphere packing or/and addition of preservatives such as organic acids or sulphites, that are in some cases inefficient to limit the growth of L. monocytogenes if a contamination has occurred. The use of protective bacteria is one of the alternative or additional methods that have been proposed for several years. Lactic acid bacteria that have been selected for their ability to limit the growth of L. monocytogenes in seafood belong to the genera Carnobacterium, Lactobacillus, Leuconostoc, Lactococcus. Some of them have been tested successfully against the pathogenic bacteria added in real products by challenge test during the shelf life of the product and their relative efficiency will be compared. In some cases, the effect of the selected lactic acid bacteria on the organoleptic characteristics of seafood has been tested by sensorial and/or physicochemical analysis. Finally, the mode of action of these bacteria involving bacteriocins, nutritional competitions or contact dependent inhibition and the way it has been demonstrated will be investigated.

⁽¹⁾EFSA Journal 2015;13(1):3991