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In a context of changing food processing practices towards safer foods less formulated in salt, sugar and additives, the research of the UMR INRAE-Oniris SECALIM aims to provide knowledge on the influence of processes on microbiology and food safety. Lightly preserved seafood, such as cold-smoked fish and fish gravlax, are traditionally consumed in Europe and are of considerable economic importance. This study aimed to monitor and compare the microbiological, biochemical and sensory characteristics of three processed products obtained from the same batch of salmon, throughout refrigerated storage: cold-smoked salmon stored under vacuum packaging or a modified atmosphere packaging and salmon dill gravlax. Microbiological analysis was performed using conventional cultural methods, coupled with analysis of bacterial communities by high-throughput amplicon sequencing of 16S rRNA. The evolution of the pH, as well as the production of metabolites likely to affect the sensory qualities of the products (trimethylamine, total volatile basic nitrogen (TVBN), biogenic amines, volatile organic compounds (VOC) were measured. Sensory analysis characterized the sensory quality of products using different descriptors associated with the appearance, texture and odour of the product.

With a relatively similar initial microbiota dominated by the genera Photobacterium, Lactococcus and Lactobacillus, the three products exhibited between the fourteenth and the twenty-eighth day a significant change in their microbial composition, in connection with their processing and / or packaging conditions. By day 28, the ecosystem of cold-smoked vacuum salmon was predominantly comprised of the genera Photobacterium and, to a lesser extent, Lactococcus and Lactobacillus, while Lactobacillus was dominant  cold-smoked salmon under modified atmosphere packaging. Predominantly dominated by Enterobacteriaceae, including the genera Serratia / Yersinia, salmon gravlax exhibited greater bacterial diversity than smoked salmon, presumably due to the presence of spices and herbs and the absence of phenolic compounds. In general, the quality of the products remained acceptable throughout storage with little sensory impairment of the products. However, gravlax was the most perishable product, ahead of cold-smoked salmon under vacuum and cold-smoked salmon under modified atmosphere packaging, the latter undergoing no noticeable spoilage after thirty-five days of storage. When observed, the spoilage was associated with an increase in TVBN, biogenic amines and VOCs associated with spoilage. This study made it possible to show that the process and the nature of the packaging significantly influence the microbial composition and the quality of the finished product.

 Publication associée :

Wiernasz, N., F. Gigout, M. Cardinal, J. Cornet, J. Rohloff, P. Courcoux, E. Vigneau, S. Skírnisdottír, D. Passerini, M.-F. Pilet and F. Leroi 2021. Effect of the manufacturing process on the microbiota, organoleptic properties and volatilome of three salmon-based products. Foods 10(11). 10.3390/foods10112517.

Financement et partenariat :

This study was performed by UMR INRAE-Oniris SECALIM in collaboration with the laboratory EM³B de l’IFREMER and USC INRAE StatSC d’Oniris in Nantes in the fraework of the European project ERA-Net SAFEFISH DISH (ANR-14-COFA-0001).