While U.S. Occupation Safety and Health Administration (OSHA) laws limit the amount of gaseous ozone that workers can be exposed to, Hamil believes they should not be exposed to any at all. She recommends using it in sealed rooms and waiting until it has broken back down into oxygen before admitting workers into the area.
Enhancing Shelf Life
Another critical factor is that ozone, Hamil stresses, cannot be stored. “It must be generated and applied on-site.”
And since ozone sanitation is a cool-temperature process, storage rooms are ideal places to pump ozone gas, not only for sanitization, but to increase shelf life. “If you have ozonated air in the ripening room,” she notes, it can “inhibit any microbial growth.”
Precision is key. David McGrath, vice president of sales and marketing at Cocoa, FL-based Guardian Ozone, confirms the necessity to “monitor all systems remotely to ensure the precise concentration and dosage for the right amount of time.” Too little ozone has no impact, he says, and “too much ozone is not good for people or products.”
Christopher Ranch, LLC is headquartered in Gilroy, but has offices across the country. The California-based grower has been using ozone on its fresh garlic for over ten years.
Janette Codiga, vice president of food safety and compliance, says the company uses ozone both as an antimicrobial agent and to ensure the stated shelf life of its peeled garlic cloves.
Organic growers are interested in ozone as a chemical-free sanitizer as well, since they have fewer options than conventional produce growers.
Food Safety Implications
Yet another benefit of using ozone, according to Hamil, is that it eliminates microorganisms without leaving a residue and is more powerful than traditional chemicals. She adds that it also has the ability to remove pesticides and kills microorganisms, while simultaneously disinfecting any of the surfaces around it.
So you get the benefit of sanitizing the produce as well as the conveyor belt, floors, and drains. “It’s absolutely lethal to all microorganisms,” she emphasizes, and it can break down biofilms on facility surfaces. “Chlorine can kill the top layer, but listeria can grow beneath the surface.”
Codiga says ozone is also easier on machinery. “Prior to using the ozone system, we used a chlorine bath for the garlic. It was hard on the equipment and more pieces of equipment had to be repaired or replaced. The ozone system is much easier on the equipment.”
Suslow cautions, however, that facilities must be careful in evaluating equipment before implementing ozone. “Be concerned with compatibility of materials in and around ozone,” he notes.