“It’s highly reactive and therefore highly corrosive. If it’s in water systems, it’s not a big deal as long as you’re aware of it,” Suslow advises. And over time, he says ozone can degrade door and valve seals as well as brass fittings.
Hamil believes ozone improves the health of any facility, and claims “no plant in the world that has had a microorganism outbreak was using ozone.” She added that while microorganisms can build up a tolerance to traditional chemicals, they can’t build up a tolerance to ozone.
There are also no containers to lug around or dispose of, and ozone is safer for employees to work with, requiring no personal protection devices when used correctly.
On the flip side, there are a few limitations. Suslow’s University of California study found that while gaseous ozone in storage rooms is effective, it is not reliable in wiping out infections that may reside “within or beneath the plant surface.”
Ozone is also not a be-all end-all for sanitation, but part of a process. It does not take the place of wash water or chlorine rinses.
Hamil affirms that ozone does not replace all chemicals. “You don’t wash with it, you sanitize with it. So you still need chemicals for washing. You still need to clean first, and then go back to sanitize.”
In some cases, she adds, items may not be prewashed, but sprayed with aqueous ozone and then have wax added for final shipment.
“In a nutshell, aqueous ozone is generally not used as a wash as its surfactant qualities are not as fast as a soap-based product,” explains Hamil, “but ozone is an extraordinarily powerful sanitizer.”
While gaseous ozone can be used in storage coolers to sanitize and extend shelf life, its effectiveness can also be impaired when produce is tightly packed in bins or cartons.
Taking the Leap
So if a supplier wants to use ozone, what’s the first step? As a food safety consultant, Hamil says she visits a prospective customer’s plant to evaluate how ozone might best be used within the operation, including the size of necessary machinery, the appropriate dosage, and best location(s).
“Be strategic,” Suslow says. “If you’re going to do a sizeable system, you have to do a very good analysis.” And this includes knowing what materials are compatible with ozone and if any equipment will need to be retrofitted before implementation.
Almost any operation using some type of wash water is a potential ozone user. The type of system recommended depends on multiple factors, including the size of the plant and water flow rate on the lines, which may vary from section to section.