Ozone Sterilization: Another Option for Healthcare in the 21st Century

Abstract

BACKGROUND: Ozone has been recognized as a safe disinfectant for water and food for many years now. It can be safely used in both gaseous and aqueous forms as an antimicrobial agent in the treatment, storage, and processing of foods, including meat and poultry. The company, TSO3. Inc., has developed a unique sterilization process for heat-sensitive materials using ozone as the sterilizing agent. The microbial efficacy of the TSO3 125L Sterilizer was established by demonstrating that the process could achieve a Sterility Assurance Level of 10–6 (SAL-6). METHODS: An overkill approach was used for the demonstration of SAL-6 for viruses, fungi, vegetative bacteria, mycobacteria, and bacterial spores. Paper-strip carriers were inoculated with 106 colony-forming unit (CFU) of the studied microorganisms only, or by a mixture of hard water (400 ppm) or serum (10%). Contaminated carriers were distributed in a validation load and exposed to partial cycle in the TSO3 125L sterilizer. D-values were calculated using the limited Holcomb-Spearman-Karber methods. Inoculated medical devices and narrow lumens were also tested as actual medical devices in hospital loads (in-use test). RESULTS: Resistance of the microorganisms tested to the process is, from less to more resistant, vegetative bacteria < fungi < mycobacteria < bacterial spores. Among the spore-forming bacteria, spores of Geobacillus stearothermophilus are the most resistant. Simulated-use testing demonstrates the efficacy of the process to sterilize lumens devices, hinges, and other instrument challenges. In-use testing confirms these results. CONCLUSION: In September 2003, the company obtained its United States 510K clearance to market. As infection control professionals continue to search for ways to lower the number of nosocomial infections in hospital, this technology can present some significant benefits for the sterilization low-temperature medical devices.