Enhanced sterilization efficacy using UV-activated humid ozone

The sterilization efficacy of the UV-activated humid ozone (O₃) method was systematically evaluated under controlled conditions involving UV irradiation, ozone generation, and humidity. This technique leverages the synergistic effects of 254 nm UV light, ozone, and water vapor to generate reactive oxygen species (ROS) for microbial inactivation. While ozone alone created a moderate oxidative environment, complete sterilization confirmed using Bacillus atrophaeus spore biological indicators (8 × 10⁶ CFU/carrier) occurred only when all three components were combined. Treatments with UV and water vapor alone failed to achieve sterilization, highlighting ozone’s critical role in initiating ROS formation. Although direct ROS quantification was not conducted, qualitative analysis using high-sensitivity colorimetric indicators enabled effective comparisons across treatment conditions. The specific contributions of individual ROS remain to be quantified in future work. Overall, the UV-activated humid ozone method offers a fast, low-temperature, and eco-friendly alternative for sterilizing heat-sensitive materials in clinical, industrial, and biotechnological settings.