Bandgap-engineered BiOBr/I heterojunction reinforced PVA/CMC film integrating photodynamic antibacterial model and mechanical robustness for enhanced fruit preservation

With the escalating focus on sustainable food packaging, the concurrent demands for outstanding mechanical robustness and effective photodynamic antibacterial activity in materials designed for fruit preservation have yet to be adequately fulfilled. This study first engineered an innovative food packaging nanocomposite (CPBI) through strategic integration of BiOBr/I heterojunction within a polyvinyl alcohol/carboxymethyl cellulose (PVA/CMC) matrix, integrating photodynamic antibacterial functionality and ultra-high mechanical strength for perishable fruit preservation. The incorporation of BiOBr/I into the natural-polymer network achieved remarkable pathogen inactivation efficiencies of 97.4 % against Staphylococcus aureus and 93.8 % against Escherichia coli O157:H7 via ROS-mediated membrane peroxidation. Simultaneously, the CPBI film displayed superior mechanical properties (tensile strength: 240.1 MPa, fracture strain: 260 %). In practical storage, this film successfully extended the shelf life of cherry tomatoes to 20 days, demonstrating its highly effective fruit preservation capability. This strategy advances the evolution of intelligent packaging solutions, simultaneously addressing the tripartite challenges of material sustainability, postharvest preservation, and foodborne pathogen mitigation.