In the earth’s stratosphere, ozone exists in high concentrations and acts as a shield that absorbs most of the sun’s ultraviolet radiation, hence the term “ozone layer.” But as a sterilizing agent, ozone has a very different role.
Long used for the disinfection of drinking water, ozone is now getting more attention for its strong oxidizing properties. Tim Stoddard, CEO of Cylopss and a pioneer in the world of ozone sterilization, explains how ozone works:
How Ozone Sterilization Works
An ozone sterilizer is able to harness the unique powers of ozone by producing it inside the sterilizer from medical grade oxygen, which is commonly available in hospitals (as explained above, by applying electrical energy to combine O2 with O to form O3). This capability is well-suited for sterilizing delicate medical devices, like endoscopes, that cannot withstand the high heat and humidity of standard steam autoclaving. Approved by the FDA in 2003 as a new sterilization process for low-temperature sterilization, its microbial efficacy has been proven with a variety of microorganisms, including the most resistant Geobacillus stearothermophilus, (which is often the bacterium of choice for biological indicators).
Actually, on its own, ozone can be quite dangerous: it is toxic, corrosive and flammable, but since the ozone is produced and broken down within the sterilizer, chances of exposure to it are quite minimal. The waste ozone is destroyed by passing through a simple catalyst, which brings it back to a state of oxygen that can be safely expelled into the air.
|Needs only medical grade oxygen, which is not a dangerous gas to handle or transport||Ozone itself is a toxic and flammable gas|
|Medical-grade oxygen is readily available in hospitals all over the world, removing the additional overhead of stocking expensive sterilant||Cycle time is longer than hydrogen peroxide plasma sterilization|
|Does not leave toxic fumes or residue that must be aerated; rather converts back to oxygen that can be safely released into the air|
|If there were to ever be a leak, even very tiny amounts of ozone could be detected from its pungent smell|
|Cycle time is shorter than EtO sterilization|
|Cost per cycle is cheaper than EtO since oxygen is cheaper to acquire than EtO|
How Popular Is Ozone Sterilization?
In low-temperature sterilization, as we have posted on our blog, there are several options. The most popular remain Ethylene Oxide (EtO), Formaldehyde, and Hydrogen Peroxide Plasma. Today, however, with the health risks associated with formaldehyde becoming more and more worrisome, many hospitals and sterilization departments are phasing out these options. Hydrogen peroxide plasma remains popular, and we are seeing an increased interest in ozone sterilization as a safe and cost-effective alternative. Another type of low-temperature sterilization method gaining attention is nitrogen dioxide sterilization.
Optimistic about Ozone
Ozone has exciting potential as a sterilizing agent in the world of low-temperature sterilization. After all, it has been used for many years to disinfect drinking water, food, and air. Now that the infection control industry has figured out how to maximize its germicidal properties inside a sterilizer, we expect to see more ozone sterilizers in hospital CSSD/SPD rooms. It’s relatively safe and its cost-effectivity will ultimately prove to be a selling point over the more dangerous alternatives, such as formaldehyde. And in some ozone sterilizers it is already being paired with hydrogen peroxide plasma in order to perform a double-fronted assault on microorganisms. One thing is for sure: we will be hearing more in the coming years about ozone as a viable alternative for low-temperature sterilization.