Ifremer: four lactic acid bacteria strains from seafood limit the growth of Listeria monocytogenes in smoked salmon, gravlax and cooked shrimp; industrial validation expected in 2027
In a text for the Fête de la science published on 22 September 2026, the French marine research institute Ifremer described its biopreservation method: selected lactic acid bacteria added in large numbers to the product inhibit pathogenic and spoilage bacteria. Losses and waste of seafood are estimated at 30% of the total volume caught.
- The method, developed over 30 years with the ONIRIS VetAgroBio Nantes school, starts with isolating bacteria from fish and crustaceans, processed or not, in various packaging. The Ifremer collection holds more than 5,000 strains, including many lactic acid bacteria adapted to seafood conditions (low temperatures, low sugar content). Each strain is tested for its ability to kill or inhibit the main pathogenic and spoilage bacteria, and the most promising undergo safety checks: no toxin production, no transmissible antibiotic resistance and no virulence genes.
- The selected strains are added at about 5 million bacteria per gram of food and the product is stored under typical (0–4 °C) or abusive (8 °C) conditions simulating a break in the cold chain. Effectiveness against pathogens and the effect on sensory quality are assessed by a sensory panel of about 20 people; the strain must also be producible in quantity and keep its properties after freeze-drying.
- Four strains of the species Carnobacterium maltaromaticum, Carnobacterium divergens and Lactococcus piscium limit the growth of Listeria monocytogenes in smoked salmon, gravlax and cooked shrimp while slowing spoilage; a Latilactobacillus sakei strain was patented for preventing histamine formation in tuna. The results were licensed to starter culture producers, who also developed applications in meat and dairy products.
- In the European projects MICROORC and FOODGUARD Ifremer is testing the technology in less processed products (e.g. with reduced salt) and with more sustainable packaging; industrial validation in French smoked salmon plants is expected for 2027, and trials on farmed sea bream were successful. The regulatory status of protective bacteria (ingredient or additive) is still under discussion at EU level. MICROORC (EU grant agreement No 101136248) develops, among other things, shelf-life prediction models using microbiome data, time-temperature indicators, rapid assays for microbial spoilage indicators and microbiome-based protection technologies to replace synthetic chemicals.