Advancing Food Safety and Public Health through Visible-Light Responsive Antimicrobial Materials

Abstract

Bacterial contamination remains a critical challenge for public health, accounting for an estimated 1.2 million foodborne illnesses and 1.4 million healthcare-associated infections annually. The widespread use of antibiotics has further accelerated the emergence of antimicrobial resistance (AMR), necessitating alternative, non-antibiotic intervention strategies. In this study, we developed and evaluated a visible-light-responsive antibacterial film based on a cellulose matrix incorporating a photosensitizing dye and modified titanium dioxide (TiO₂) nanoparticles. The optical properties of the material were characterized across a range of wavelengths to confirm visible-light absorption. Reactive oxygen species (ROS) generation under varying light intensities was quantified and qualitatively assessed, with singlet oxygen (¹O₂) and hydrogen peroxide (H₂O₂) identified as the primary antimicrobial agents. Antibacterial efficacy was evaluated (n = 3) against multiple bacterial species under different light intensities at 4 °C in liquids, on fresh produce, chicken, and stainless steel surfaces. The incorporation of the photosensitizer dye with the titanium dioxide particles enabled activation under low-intensity visible light (1000–3000 lux), with higher light intensities (6000 lux) significantly enhancing ROS production and antibacterial performance.The film demonstrated broad-spectrum antimicrobial activity in a variety of applications (liquid, dry surface and on food). Notably, It led to a 3-log CFU reduction in Salmonella enterica on mango slices within 48 hours. Under 3000 lux (grocery indoor light intensity), the film inactivated methicillin resistant Staphylococcus aureus (MRSA) and Listeria monocytogenes on stainless steel surface by 5 logs (99.999%) and 1log (90%), respectively. However, the antibacterial efficacy decreased as the light intensity decreased to 1000 lux. Furthermore, while the film is effective on fresh produce, it underperforms on protein-rich matrices such as chicken. Additionally, effective bacterial inactivation required direct physical contact between the film and the contaminated surface. Overall, this visible-light photocatalytic material provides an effective, non-antibiotic approach for bacterial inactivation under low-intensity visible light by generating ROS. This innovative solution offers potential applications in food safety and promoting public health.