Anti-bacterial and anti-biofilm effect of punicalagin against Pseudomonas fluorescens and its application in reducing spoilage of tilapia fillets induced by Pseudomonas fluorescens

The antimicrobial efficacy of punicalagin against foodborne pathogens has been extensively studied, yet its impact on spoilage microorganisms remains poorly characterized. This study aimed to evaluate punicalagin's inhibitory effects on Pseudomonas fluorescens and explore its potential application in tilapia preservation. Growth curve analysis showend that punicalagin effetively inhibited the growth of Pseudomonas fluorescens. In addition, punicalagin triggered intracellular potassium ion efflux and leakage of nucleic acids and protein. Scanning electron microscopy revealed compromised cell membrane integrity after punicalagin treatment. Furthermore, punicalagin exposure reduced intracellular ATP levels and elevated reactive oxygen species accumulation. Concurrently, it effectively suppressed biofilm formation and destroyed preformed biofilms. In tilapia spiked with Pseudomonas fluorescens, punicalagin markedly attenuated spoilage progression, as evidenced by diminished protein degradation and lipid oxidation. These collective findings indicate that punicalagin exhibit antimicrobial and anti-biofilm activities against Pseudomonas fluorescens, highlighting its potential as a natural preservative for aquatic products.