Preparation of photosensitive antibacterial nanocomposite film and its preservation effect on pork loin

Enhancing antimicrobial activity of food packaging is highly desirable and challenging. In this study, biodegradable and effective antibacterial nanocomposite films were prepared by incorporating self-assembled nanoparticles of the natural photosensitizer berberine and 3,4,5-methoxy cinnamic acid into the gelatin-based film matrixes. The self-assembled berberine-3,4,5-methoxycinnamic acid nanoparticles (BT NPs) exhibit aggregation-induced emission activity when exposed to visible light, resulting in enhanced antibacterial activity. With the addition of BT NPs, the nanocomposite films showed improved UV shielding ability, hydrophobicity, and water vapor transmission rate. More importantly, the nanocomposite films utilized sunlight to produce reactive oxygen species (ROS) and thus inactivated all the inoculated Staphylococcus aureus within merely 15 min. Additionally, even under dark, NPs exhibited adequate antimicrobial activity. Finally, the antimicrobial effect of packaging tests on pork tenderloin samples was confirmed, as the total bacterial count of the samples remained below 6 log CFU/g on the 10 d. Therefore, this study offers new perspectives on the development of natural and potent antimicrobial food packaging.