Effects of Fucoidan on the Inhibition of Biofilm Formation of Salmonella enterica Subsp. enterica Serovar Typhimurium on Seafoods and Its Molecular Antibiofilm Mechanisms

Abstract

Foodborne illnesses, particularly those caused by Salmonella enterica subsp. enterica Serovar Typhimurium, present a significant challenge to public health, especially within the seafood industry due to biofilm formation on foods. This study investigated the antibiofilm potential of fucoidan, a sulfated polysaccharide, against Salmonella enterica subsp. enterica Serovar Typhimurium biofilm on crab and shrimp surfaces. Fucoidan’s minimum inhibitory concentration (MIC) was determined to be 150 µg/mL. Sub-MIC (1/8, 1/4, 1/2, and MIC) were evaluated for their impact on inhibition of biofilm formation. Fucoidan treatment resulted in significant, dose-dependent inhibition in biofilm formation, achieving 2.61 log CFU/cm2 and 2.45 log CFU/cm2 reductions on crab and shrimp surfaces, respectively. FE-SEM analysis confirmed biofilm disruption and cell membrane damage. Real-time PCR showed the downregulation of quorum-sensing (luxS) and virulence (rpoS, avrA, and hilA) genes. These results propose that fucoidan has the ability as a natural antibacterial agent for controlling Salmonella enterica subsp. enterica Serovar Typhimurium biofilms in seafood processing, thereby enhancing food safety and minimizing contamination. © 2025 by the authors.