Non-migrating active antibacterial packaging and its application in grass carp fillets

Non-migrating active antibacterial packaging can provide long-term and safe effects on food preservation. It was prepared by covalently immobilizing chitosan (CS) or lysozyme (LYS) on the surface of plasma-treated polylactic acid (PLA) film. Films were characterized in terms of X-ray photoelectron spectroscopy (XPS), attenuated total reflection-Fourier transform infrared spectroscopy (ATR-FTIR), field emission scanning electron microscopy (FESEM). Laser scanning confocal microscopy (LSCM) revealed that survival of E. coli and S. aureus was inhibited on CS or LYS functionalized films. Finally, the grass carp fillets were stored at 4 °C for 9 days, and physicochemical changes and microbiological counts were determined. Results showed that CS grafted PLA film (CS-g-PLA) and LYS grafted PLA film (LYS-g-PLA) retarded the decay of fish fillets for 1 and 3 days, respectively, compared to control sample. The CS-g-PLA film inhibited the growth of bacteria more efficiently than PLA and LYS-g-PLA films (P < 0.05). Overall, this study demonstrated that grafted films are a promising non-migrating packaging material for providing antibacterial effects in packaging for fresh fish.