Attachment and biofilm formation of eight different Salmonella serotypes on three food-contact surfaces at different temperatures

Authors: Counihan, Katrina; Tilman, Shannon; Uknalis, Joseph; Mukhopadhyay, Sudarsan; Niemira, Brendan; Bermudez-Aguirre, Luz

Submitted to: Microorganisms
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/19/2025
Publication Date: 6/21/2025
Citation: Counihan, K.L., Tilman, S.M., Uknalis, J., Mukhopadhyay, S., Niemira, B.A., Bermudez-Aguirre, L.D. 2025. Attachment and biofilm formation of eight different Salmonella serotypes on three food-contact surfaces at different temperatures. Microorganisms. https://doi.org/10.3390/microorganisms13071446.
DOI: https://doi.org/10.3390/microorganisms13071446

Interpretive Summary: The presence of pathogens such as Salmonella can generate food safety risks during the production chain. This microorganism can attach to food-contact surfaces and form strong biofilms that can contaminate foods. However, there are many factors affecting the biofilm formation such as the temperature, the food-contact surface and the specific serotype of the microorganism. In this study, some of these conditions were studied, using two different temperatures (10°C and 37°C), three food-contact surfaces (stainless steel, silicone and nylon) and eight different serotypes of Salmonella cells. The biofilm formation was studied after 24 hours using conventional microbiological methods, electron microscopy and genomics. The results showed the strongest and weakest serotypes, and the effect of the environmental conditions on the biofilm formation. This information can be useful to develop efficient sanitizing interventions and support improved detection methods for the food industry.

Technical Abstract: Salmonella spp. represents a food safety risk during the production chain because of the possibility of biofilm development. This research studied the biofilm formation of eight Salmonella serotypes from diverse foodborne outbreaks on three food-contact surfaces, stainless steel, silicone, and nylon, at 10°C and 37°C. The effect of temperature was observed in slower biofilm formation at 10°C with about 5-log (cfu/cm^2) after 24 h, contrasting with 7-log (cfu/cm^2) at 37°C. The material also influenced biofilm formation with the strongest biofilms on stainless steel at 10°C and silicone at 37°C. The serotypes producing the strongest biofilms were S. Enteritidis, S. Saint Paul and S. Montevideo. The weakest serotypes were S. Senftenberg, S. Anatum, and the avirulent S. Typhimurium. The production of extra polymeric substances was evident with S. Enteritidis. The biofilm index showed the highest value for low temperature, nylon, and silicone, and for S. Montevideo, S. Enteritidis, and S. Saint Paul. The whole genome sequencing of each serovar suggested that single nucleotide polymorphisms in the curli (csg) genes may have contributed to the strong biofilm forming ability of S. Montevideo and S. Saint Paul and the weaker ability of S. Senftenberg. These results can help with the correct development of sanitizing interventions, based on the Salmonella strain of concern.