March 15, 2007 4:00 AM PDT
Killing fungi softly, with ozone
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Novazone doesn't concentrate on in-field killing like biopesticide companies. Instead, it focuses on making equipment for post-harvest storage and processing. Right now, the products are mostly installed in warehouses and cool rooms, where apples or lemons might sit for a year before making it to store shelves. One cherry grower has already replaced its traditional cleaning system--a vat filled with water and chlorine--with an ozone bathing system.
Soon, Novazone will come out with mobile units that can spray ozone onto fruit being ferried by trucks. Systems will also be prepared for large, big-box retailers.
Along with curbing chemicals, ozone can cut the amount of food that gets wasted, a major problem for food producers. In 2006, roughly 20 percent of the grapes picked in Chile never made it to store shelves because of pathogens.
In a test conducted by the U.S. Department of Agriculture, Anjou pears were locked in cold storage for six months and treated by Novazone's ozone system. Airborne mold was reduced by 100 percent compared with ordinary circumstances, while mold on fruit bins was down 95 percent. Food decay was reduced significantly, as well.
Three weeks after coming out of the locker, the pears were tested again, this time for skin and surface pressure. The ozone-treated pears were slightly harder, and thus would last a few weeks longer on a store shelf than untreated pears. The Food and Drug Administration approved ozone as a substance that can disinfect food through contact in 2001. Field studies at Paramount Farms (using kiwifruit) and Sunkist (using lemons) found that the fruit shelf life increased by several weeks.
Along with killing pathogens, ozone can slow down natural ripening processes. Ethylene, a gas that gets released by bananas and other substances, can cause apples, pears and other fruits to ripen at a faster rate. Ozone converts ethylene to carbon dioxide and thereby arrests the ripening process, allowing the fruit to live longer.
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