Application of 405 nm visible light to selected bacterial species in animal husbandry

The antimicrobial effect of light at specific wavelengths is currently used for sanitation procedures in various types of facilities. The aim of this study was to verify the bactericidal and fungicidal activity of 405 nm light as a safer alternative to ultraviolet C (UVC) radiation that could be used for disinfection in animal housing. Commercially available lamp located in the experimental room was used to emit the 405 nm radiation. For most of the bacterial species tested, there was no decrease in colony forming units after 8-h and 24-h radiation. Significant ( P < 0.01) reduction in the number of colonies was observed for 8-h and 24-h radiation application in the case of Bordetella bronchiseptica when grown on trypticase soy agar. There was also a significant reduction ( P < 0.01) in the number of colonies for Staphylococcus aureus on trypticase soy agar after 24-h radiation exposure. The results indicate a partial bactericidal effect of radiation depending on the type of bacterium irradiated, the type of nutrient medium used and the duration of radiation exposure. However, the effect of the method used in this study cannot be described as disinfectant. In the context of practical application of the technology, the factors mentioned above need to be further investigated.