Porphyrinic Metal–Organic Framework-Loaded Polycaprolactone Composite Films with a High Photodynamic Antibacterial Activity for the Preservation of Fresh-Cut Apples

Food-borne diseases caused by fresh fruits and vegetables seriously threaten human health. The polycaprolactone (PCL) polymer with good biodegradability has drawn growing interest in packaging and protecting of fresh fruits and vegetables. The disadvantage of pure PCL as a packaging material is the lack of the antibacterial function. Photodynamic sterilization as a safe and effective antibacterial method is now the emerging means for food safety. Therefore, the porphyrinic metal–organic framework MOF-545 as a highly effective photosensitizer was incorporated with PCL to prepare a biodegradable antibacterial composite film. The incorporation of MOF-545 nanorods significantly enhanced the hydrophilicity and mechanical strength of the film while slightly decreasing the transparency. The PCL/MOF-545 (10%) film exhibited the strongest antibacterial activity under a white LED light. This film was used for packaging fresh-cut apples and effectively killed 96% of the microorganisms, also delaying the apples' discoloration and water loss. The PCL/MOF-545 film showed great potential for the antibacterial packaging of fruits and vegetables.