Thermal-activated Polydopamine bilayer film exhibits dual-mode synergistic antibacterial properties for enhanced salmon preservation

Foodborne pathogens threaten food safety and human health, prompting the need for innovative preservation solutions. Polydopamine endowed with photothermal properties represents a novel material for the inhibition of foodborne pathogens. This study develops a bilayer antibacterial film using polydopamine-berberine nanoparticles (PDA-BBR), leveraging dual-mode synergistic antibacterial effects through chemical and photothermal mechanisms. The film, incorporating starch and polylactic acid layers, was prepared via solvent casting and characterized for mechanical properties, water vapor permeability (WVP), and antibacterial efficacy. The results revealed that the 2.0 % PDA-BBR film achieved a tensile strength of 4.00 MPa, a WVP of 2.30 × 10 −11  g/m·s·Pa, and over 95 % inhibition against Escherichia coli and Staphylococcus aureus . Moreover, the film preserved salmon quality by maintaining texture, lowering total volatile basic nitrogen to 16.19 mg/100 g, and inhibiting spoilage during 9 days of storage at 4 °C. These findings highlight PDA-BBR film as a promising food preservation approach with enhanced antibacterial and preservation performance.