Fabrication and characterization of LDPE/silver-copper/titanium dioxide nanocomposite films for application in Nile Tilapia (Oreochromis niloticus) packaging

Proper packaging is an essential issue in seafood safety leads to the preservation of food quality and extending the shelf life. In this study, fabrication and characterization of LDPE/Ag/TiO₂ and LDPE/Ag + Cu/TiO₂ nanocomposite films for application in Nile Tilapia packaging were evaluated. After investigation of scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), disk diffusion test, minimum inhibitory concentration, and minimum bactericidal concentration, the antimicrobial effect of produced nanocomposite films was evaluated on the Tilapia fish samples stored at 4 °C and − 20 °C for 5 and 10 days. Chemical features (pH, protein and fat concentrations, and free fatty acid profile) of the Tilapia fish covered with the produced nanocomposites and nanoparticle migration were also assessed. EDS and SEM techniques confirmed the presence of nanoparticles on the polymer surface and their relative homogeneity. The antibacterial tests of LDPE/Ag + Cu/TiO₂ nanocomposite film exhibited strong antibacterial activities against Escherichia coli and Listeria monocytogenes bacteria (P = 0.000). The microbiological tests revealed that Ag + Cu-contained film had significantly higher antimicrobial efficacy on the Nile Tilapia samples (P < 0.05). The overall result of the series of chemical experiments showed that Tilapia samples packed in Ag + Cu film had the least changes in chemical properties compared to fresh samples (P < 0.05 for pH, fat concentration, and free fatty acid profile). Besides, the migration of Ag and Cu nanoparticles from the film to Tilapia samples was slightly (the amount of Ag and Cu release was < 2.0 µg/Kg and < 10 µg/Kg, respectively). From the obtained results, it could be concluded that a film containing 2.5 % silver, 2.5 % copper, and 5 % titanium dioxide nanoparticles had the most significant antimicrobial effect on the Nile Tilapia fish. Therefore, using LDPE/Ag + Cu/TiO₂ nanocomposite film can be a promising approach to create active packaging in the seafood industry.