Breaking the biofilm barrier: vitamin C as a novel strategy against multidrug-resistant <i>Salmonella</i> Typhimurium

Abstract The emergence of multidrug-resistant (MDR), biofilm-forming Salmonella Typhimurium poses a significant threat to food safety due to their persistence in food sectors, complicating eradication efforts. This study explored the antibiofilm activity of vitamin C (VC) against MDR biofilm-forming S. Typhimurium. VC inhibited S. Typhimurium biofilms in a dose-dependent manner, with minimum inhibitory concentration of 125 mM. VC significantly disrupted the bacterial biofilm structure, creating pores in cell wall as observed through electron microscopy. The antibiofilm mechanism of VC was mediated by reactive oxygen species generation, leading to sugar and protein leakage, reduced exopolysaccharide production, and decreased quorum sensing activity. VC downregulated expression of biofilm-related genes (fimA, adrA) and upregulated genes associated with adhesion and multidrug efflux pumps (csgA, ipfE, and arcA). Importantly, VC coating on Paneer significantly extended its shelf life. These findings highlight potential of VC as promising antibiotic-free strategy to combat MDR Salmonella biofilms and enhancing food safety.