Food contact materials based on N-halamines or photosensitizers: An emerging strategy for developing “rechargeable” antibacterial properties

Background

Foodborne diseases affect approximately 600 million people each year and remain a serious global public health issue. Traditional physical, chemical and biological antibacterial methods have various drawbacks such as high cost, harmful residues, drug resistance and non-environmental friendliness. Although biodegradable and renewable antibacterial materials have emerged, the regeneration of these materials involves complex procedures and relies on specialized industrial facilities, and thus has not been widely adopted in the industry. Recently, a new sustainable antibacterial strategy has begun to emerge in the field of food contact materials. This method is inspired by rechargeable batteries. Through a simple “charging” process, the material can be repeatedly replenished to restore its antibacterial performance without changing its physical form.

Scope and approach

This review defines “rechargeable” as regenerating antibacterial activity through chemical treatment (e.g., NaClO immersion) or energy input (e.g., light exposure) without altering a material's physical form. It combines experimental data and application cases to review the forms, charging efficiency, cyclic antibacterial performance, and safety evaluation of materials.

Key findings and conclusions

The “rechargeable” antibacterial properties of food contact materials are currently achieved through two main mechanisms: N-halamine and photosensitizers. N-halamine-based materials can undergo up to 20 recharging cycles through chlorination reactions in diluted bleach solutions, while still maintaining outstanding antibacterial efficacy (>3-log bacterial reduction). Materials containing photosensitizers (such as vitamin K3 (VK3) and 3,3′,4,4′-benzophenone tetracarboxylic dianhydride) continuously “charge” under light, storing reactive oxygen species (ROS), which can be continuously released in the dark to achieve long-lasting antibacterial effects. Photosensitizer-based materials can retain approximately 70 % of their initial photocatalytic activity and maintain effective antibacterial performance (with a bacterial reduction of 5 log) after at least 4 charge-discharge cycles. This “rechargeable” strategy has the potential to facilitate the transition of food contact materials from the “single-use” model to a “recycling” model.