Ozone to improve fresh fruit, vegetable safety.

When it comes to the safety of fruit and vegetables, the industry has relied on traditional sanitizing agents, which include water with or without a

sanitizing agent. Chlorine is the most widely used sanitizing agent available for fresh produce. However, its ability to kill bacteria is limited. The most that can be expected with chlorine is a 1- to 2-log reduction in microbial populations.

Research has shown that ozone has the potential to make fresh produce safe to consume, offering more benefits than chlorine. Ozone can replace chlorine in this application because it is 1.5 times stronger than chlorine and is effective over a much wider spectrum of microorganisms than chlorine and other disinfectants.

Ozone kills bacteria, such as E. coli, Listeria and other pathogens, much more rapidly than chlorine. It also is free of chemical residues. It decomposes into simple oxygen with no safety concerns about the consumption of residuals of ozone in a treated food product.

Fruits and vegetables can first be washed in ozonated water, and the wash water can be recaptured and treated using ozonation and filtration. The treated wash water is free of bacteria, color and suspended solids, and it can be recycled to reduce the amount of water usage. Unlike conventional chlorine-based washing systems, wastewater from the ozonation process does not contain chemical residues. Ozone destroys pesticides and chlorinated byproducts.

Gaseous ozone is a strong sanitation and fumigation agent and can sanitize product in a storage room, as well as when it is shipped, to prevent bacteria, mold and yeast from forming on the food surface. Ozone eliminates undesirable flavor produced by bacteria and chemically removes ethylene gas to slow the ripening process of a product. It makes possible the expansion of distribution routes.

Many applications in the produce industry can benefit from ozone use. These include the sterilization of process water, especially to prevent cross-contamination; the cold storage of fruits and vegetables to protect against bacteria and mold; the washing of fruits and vegetables; and the recycling of process water.

Before implementing ozone technology, though, you should understand completely your facility's process flow and determine exactly at which point the ozone will find its best use; conduct pilot trials; and know the water and wastewater parameters.

Further information. Liangji Xu, Praxair Inc., 7000 High Grove Blvd., Burr Ridge, IL 60521; phone [phone]; fax: [phone]; URL: www.praxair.com.