UW clean-air technology headed for the produce section

Grocery stores with a UW-invented device installed may add up to a week of fresh life to their fruits and vegetables. The invention, which removes the plant hormone ethylene from the air, is now being marketed to stores by a Georgia company.

A UW–Madison technology that helped plants thrive in outer space may soon be landing in grocery stores, helping extend the freshness of fruits and vegetables.

The technology cleans air of ethylene, a natural hormone that causes plants to prematurely wither and spoil. Marc Anderson, a UW–Madison professor of environmental engineering and materials science, developed the technology for a series of plant-growth experiments aboard the NASA space shuttle.

Now a Georgia-based company will tap its earthly applications as a way to help retailers win the battle against yellowing broccoli, rusty lettuce, mushy fruit and droopy flowers.

KES Irrigation Systems of suburban Atlanta has purchased a license to market Anderson’s technology, which is patented through the Wisconsin Alumni Research Foundation. KES President John J. Hayman Jr. says the company will have the device commercially available this summer.

“We’re really pleased to get this technology out on the street,” says Anderson. “There are a tremendous number of applied uses, and KES is going to go after the markets in food and plant storage.”

The device, which KES named Bio-Kleen, employs a novel approach to reducing ethylene buildup. It uses the material titanium dioxide as a catalyst to break down ethylene into the harmless byproducts of carbon dioxide and water vapor. The chemical reaction is triggered by a process called photocatalysis, in which ultraviolet light is used to activate the titanium particles.

Hayman says this process has distinct advantages over current ethylene removal technologies on the market. Since the ethylene is eliminated, rather than filtered or collected, the device requires virtually no maintenance. The ultraviolet lights have also been shown to reduce bacteria, molds and odors from storage rooms, he says.

“My company is devoted to preserving the shelf life, display life and home life of products,” says Hayman. “A lot of the things we produce are not exactly rocket science. But this is rocket science, considering where the technology came from.”

KES produces misting and humidity systems for the grocery and floral industry, as well as ethylene removal systems. The company plans to publicly debut a prototype of Bio-Kleen at the Food Merchandisers Institute conference May 3-5 in Chicago.

Hayman estimates that controlling ethylene in storage rooms and displays can increase the shelf-life of perishable items by more than a week. With prices of fresh produce and flowers increasing, retailers and consumers are more concerned about reducing spoilage, he says.

Ethylene removal is a crucial link in the NASA plant-growth projects, says Ray Bula, director of the Wisconsin Center for Space Automation and Robotics. The center has flown six missions with the NASA space shuttle since 1993, using a special plant-growth chamber that carefully controls the growing environment.

Ethylene concentrations would be high enough to kill the plants without Anderson’s system, Bula says. WCSAR used Anderson’s technology to custom build an ethylene scrubber for plant experiments.

The system only removes about 50 percent of the ethylene in the air, Bula says. But the air continuously passes through the device, which keeps concentrations of the gas from building up. Bula says ethylene concentrations above 50 parts per billion can harm plants.

Ethylene is produced naturally by plants, and serves as a chemical cue that tells the plants to begin ripening or aging. But too much ethylene will cause the plants to prematurely age and spoil.

Anderson has numerous patents with WARF, which have commercial potential ranging from home air purifiers to cleaners of polluted water. Richard Leazer, director of WARF, says this project clearly illustrates the public benefits of technology transfer.

“I think what it proves is that universities are a very diverse source of technologies, and we’re trying to find ways to make them available to the public,” Leazer says.