Brochothrix thermosphacta, une bactérie responsable de l’altération des aliments capable de former des biofilms

Food spoilage results in a deterioration of sensory qualities (odor, taste, texture), which is primarily caused by the metabolism of so-called spoilage bacteria and leads to considerable food losses for the food industry. Brochothrix thermosphacta is considered a major spoilage agent in meat and seafood products. 

This bacterium serves as a model for scientists at SECALIM who are seeking to understand its ability to establish a long-term presence in industrial environments, particularly through its capacity to form biofilms. This ability to form biofilms has been explored very little to date in this bacterium. 

In this study, the ability to form biofilms was evaluated for 30 strains of B. thermosphacta from various sources (shrimp, salmon, meat, cheese, slaughterhouse environment, etc.), using a set of complementary tests (biofilm ring test, crystal violet staining, and analysis of laser-scanning confocal microscopy images). 

Two main groups of strains were identified: a group of 23 strains classified as low biofilm producers and a group of 7 strains classified as high biofilm producers. The latter were isolated from seafood: three from fish, three from shrimp, and one from a salmon filleting machine.

This study provides new insights into the characteristics of B. thermosphacta and its ability to adhere to and colonize surfaces by forming biofilms. The cohesion, thickness, volume, surface area, and cell concentration of the biofilms formed by B. thermosphacta could explain its presence at industrial sites.

A study of (i) its ability to form biofilms on various abiotic surfaces (e.g., stainless steel, polystyrene, polyurethane, and polycarbonate) typically used in the food industry, (ii) its ability to form biofilms at the low temperatures found in food processing plants, and (iii) its interactions with other microbial communities present within biofilms would provide a better understanding of its persistence in  food processing environments.

Related publications:

• Gaillac, A., Misery, B., Rezé, S., Briandet, R., Prévost, H., Jaffrès, E., 2026. Insight into the transcriptome profile of mature biofilm produced by Brochothrix thermosphacta at 25 and 8 °C. Food Microbiology139, 105126. https://doi.org/10.1016/j.fm.2026.105126
• Gaillac, A., C. Gourin, L. Dubreil, R. Briandet, H. Prévost and E. Jaffrès 2024. Biofilm formation of the food spoiler Brochothrix thermosphacta on different industrial surface materials using a biofilm reactor. Food Microbiology 120: 104457. https://doi.org/10.1016/j.fm.2023.104457.
• Gaillac A, Briandet R, Delahaye E, Deschamps J, Vigneau E, Courcoux P, et al. Exploring the diversity of biofilm formation by the food spoiler Brochothrix thermosphacta. Microorganisms. 2022 2022 Dec;10(12). https://doi.org/10.3390/microorganisms10122474

Funding and partnership: This study was conducted at the INRAE-Oniris SECALIM unit in collaboration with the Micalis Institute and the StatSC unit at Oniris.