Efficacy of cost-effective UV-light for Salmonella elimination

Abstract

Salmonella is a pathogenic bacterium that has caused multiple outbreaks in food and waterborne fields. Microorganisms such as Salmonella are floating in the air, and contaminated samples like food and water can be effectively inactivated by ultraviolet (UV) disinfection. The effectiveness of UV-A disinfection against Salmonella, rather than UV-C and UV-B spectra, must be assessed and optimized to investigate easier handling, effective, safe, cost-effective, and efficient UV disinfection techniques. Assessing the antibacterial potential of 365nm (UV-A) portable flashlight exposure against Salmonella at varying irradiance conditions is the objective of this study. At a fixed interval time of 15 minutes, dosages of different irradiance were applied to investigate their effect on Salmonella cell viability. Salmonella cell counts were significantly reduced by the applied light pulses, which also demonstrated a notable inactivation efficacy. The cell counts were evaluated by the plate count technique using the colony-forming unit (CFU). The results confirmed that the 365nm UV light is a potential means of sterilization and deactivation of Salmonella without applying chemicals or nanoparticles. It is demonstrated that the 365nm flashlight's antibacterial effectiveness was significantly influenced by the light irradiance doses. This study is the first, to our knowledge, to report on the effectiveness of UV-A handheld flashlights in deactivating Salmonella bacterial species, demonstrating the technology's potential as a substitute for the conventional UV lamps used in industry sterilization.