In vitro and in situ abrogation of biofilm formation in E. coli by vitamin C through ROS generation, disruption of quorum sensing and exopolysaccharide production

•Pro-oxidant concentrations of VitC (125 mM) exhibited anti-microbial & anti-biofilm activity.•VitC impairs metabolic activity, QS & EPS production in E. coli biofilms.•VitC mediates ROS generation inducing protein & sugar leakage & causing cell death.•VitC-treated bacterial cells effectively downregulated biofilm forming genes.•In situ reduction of E. coli viability via VitC coating of paneer supported enhanced shelf-life. Emergence of antimicrobial drug-resistance amongst food-borne pathogens has led to severe deficit of available therapeutics and requires novel interventions. This study determined the activity of vitamin C (VitC), a natural antioxidant as powerful antibacterial agent against multidrug-resistant (MDR), biofilm-forming E. coli. Our findings revealed that VitC wield antibacterial action in dose-time dependent manner with minimum inhibitory concentration (MIC) of 125 mM. At these concentrations VitC impaired quorum sensing (QS) and exopolysaccharide (EPS) production and induced sugar and protein leakage from the bacterial cells by virtue of reactive oxygen species (ROS) generation. Furthermore, VitC-treated bacteria showed downregulation of genes underpinning biofilm signaling (luxS) and regulation (bssR) by up to 27-folds. Finally, this study demonstrated the promising antimicrobial application of VitC, in situ, in Indian soft cheese (paneer) when applied as a coating. Therefore, VitC can be applied as natural and safe ‘antimicrobial’ against biofilm-forming bacteria in food systems vis-à-vis other conventional antimicrobials.