Photocatalytic ZnO-doped polyester filters for reducing airborne cross-contamination by foodborne pathogens in storage environments

Effective air purification is crucial for controlling airborne contamination, especially in food storage environments where microbial cross-contamination can compromise food safety. Conventional filtration methods often suffer from microbial accumulation, leading to decreased efficiency and potential recontamination. This study aimed to develop a polyester-based nonwoven filter doped with zinc oxide nanoparticles (ZnO NPs) synthesized using a green method involving banana peel extract. Two embedding methods, padding and in situ synthesis, were optimized for pH and temperature to enhance nanoparticle deposition and antimicrobial activity. The optimal conditions were determined to be pH 12 at 25 °C for in situ synthesis, achieving superior ZnO loading and photocatalytic activity under UVA irradiation. ZnO-doped filters were assembled into the UVLED module in a 512 L aerobiology chamber simulating refrigerator conditions, achieving more than 3-log reduction against aerosolized foodborne pathogens, Escherichia coli O157:H7, Salmonella Typhimurium, and Listeria monocytogenes. Structural characterization using SEM and FT-IR confirmed uniform nanoparticle distribution and stable embedding within the polyester matrix. The developed ZnO-doped polyester filters provide robust and reusable air purification capabilities, highlighting their potential as sustainable and effective solutions for improving microbial safety in food preservation environments.