At the present time the causes of spoilage in vacuum-packaged cold-smoked fish, are largely unknown. Specific spoilage organisms have not been identified, nor the biochemical or physical course(s) of degradation known. Similarly, there are no agreed measures of quality of cold-smoked fish nor means of estimating shelf-life. This Proposal seeks to understand the causes of deterioration, and to establish objective quality indices. On determining the mechanisms of loss of quality, it will be possible to develop rapid, simple, quantitative, microbiological and physicochemical means for their quality measurement in cold-smoked fish, leading to potential methods for estimating shelf-life.
Cold-smoked fish are often contaminated with Listeria monocytogenes, an organism capable of causing serious, often fatal, disease in susceptible individuals. Although no cases of listeriosis have been attributed to consumption of cold-smoked fish, it is clearly necessary to minimise the risk to consumers from this hazard in food. This Proposal will investigate the frequency of occurrence of this organism in European cold-smoked fish and the biotypes present, and compare these with biotypes isolated from other foods and from cases of listeriosis by reference to work in other laboratories. The Proposal will establish the source(s) of the organism, and the route(s) of contamination within processing facilities, by determining the spread of biotypes. The efficacy of fish processing and sanitising procedures in controlling Listeria spp. within the processing plants will be studied, and the effects of modifications to procedures evaluated.
Several strains of inhibitory lactic acid bacteria are available from current or previous research projects funded by the EU Commission, and are held by some of the Partners in this Proposal. Such strains will be examined for their ability to kill or inhibit L. monocytogenes and specific spoilage organisms in conditions simulating cold-smoked fish. The application of these selected lactic acid bacteria and/or their inhibitory products (e.g. bacteriocins) and already shown to be effective against Listeria spp. and spoilage organisms in other situations, will be investigated as additional hurdles for the control or elimination of L. monocytogenes in cold-smoked fish, and to extend the shelf-life.
Funding SchemeCSC - Cost-sharing contracts
KT22 7RY Leatherhead, Surrey