Multiscale Evaluation of Quercetin Against Vibrio parahaemolyticus and Vibrio vulnificus in Seafood and Food-Contact Surfaces

Vibrio parahaemolyticus and Vibrio vulnificus biofilms pose a major challenge to seafood safety owing to their persistence on food-contact surfaces and increased tolerance to antimicrobial interventions. This study investigated the antibiofilm efficacy and mechanisms of quercetin using integrated structural, physiological, and molecular approaches. Quercetin exhibited concentration-dependent biofilm inhibition and reduced mature biofilms on abiotic surfaces, while its efficacy in inhibiting biofilm formation was evaluated on seafood. Quercetin suppressed early biofilm establishment by reducing cell surface hydrophobicity, bacterial adhesion, autoaggregation, motility, cellular respiration, and ATP production, thereby limiting bacterial attachment and microcolony formation. Fourier-transform infrared spectroscopy revealed changes in the EPS-associated spectral profiles of both species, indicating alterations in the biochemical composition of the biofilm matrix. These spectral changes varied between V. vulnificus and V. parahaemolyticus. Gene expression analysis demonstrated coordinated downregulation of quorum sensing (QS), adhesion, and EPS biosynthesis genes, accompanied by increased membrane permeability, intracellular protein leakage, and metabolic dysfunction. In a 6 h screen, 1/2 MIC caused only minor changes in the color and texture of shrimp and oyster, whereas MIC caused larger changes; no cytotoxicity was detected under the tested conditions. Collectively, these findings demonstrate that quercetin disrupts Vibrio biofilms through coordinated mechanisms with limited short-term effects on seafood color and texture at 1/2 MIC, supporting further evaluation as a natural, industry-relevant strategy for controlling seafood-associated Vibrio biofilms and improving seafood safety.