(March 17) Accent lighting might enhance the color of a blueberry or draw attention to the yellow peel of a banana, but it also brings out an unwanted color in potatoes.

A University of Idaho study, released in January by the Idaho Potato Commission, Eagle, showed that bright overhead lights speed the rate at which potatoes turn green.

Scientists evaluated six different types of lights — fluorescents (two kinds), halogen, ceramic metal halide, fiber optic and fluorescent with a filter. During nine days in lighting comparable to retail levels, potatoes under fiber optic lighting turned green at the slowest rate.

The study showed that fiber optic lighting, or a combination of fiber optic accent lighting and standard fluorescent lighting, helped retard greening while still highlighting the product for consumers.

“The difficulty is that you can’t plug fiber optic lights into an old system,” said Nora Olsen, extension potato specialist at the University of Idaho Extension, Twin Falls. “You would have to have a new system installed.”

Olsen said potatoes studied under fiber optic lights had a shelf life a day longer than the other spuds in the study. The question for retailers is whether the additional 24 hours warrant investing in new lights.


Seth Pemsler, vice president of retail merchandising for the Idaho Potato Commission, said that although installing new lighting could be cost prohibitive for retailers, the study’s findings could be valuable for chains that are building stores or retrofitting older stores.

“You have to look at the cost of doing it and the cost to maintain it,” said Keith Tarver, manager of electrical systems for Boise, Idaho-based Albertson’s Inc., which participated in the study. “What we use, and a lot of people in the industry do, is ceramic metal halide. It’s the worst thing you can do to a potato.”

Fiber optic lights use emitters, which means the actual lamps — and the heat they generate — can be several feet away from the product retailers are trying to spotlight. Potatoes under fiber optic lighting stayed about a degree cooler than the potatoes studied under other types of lighting.

Fiber optic lamps are easier on potatoes but cost much more than some alternatives. Tarver said a fiber optic lamp lasts 10,000 hours to 16,000 hours and costs about $70. Because fiber optics use emitters, only a few lamps would be needed to light a display.

A retailer would need about six lamps to light a display with fluorescent lights, but they last about 30,000 hours and cost only $2-3 each, Tarver said. Ceramic metal halide lamps last 10,000 to 16,000 hours and cost about $35. Tarver said four to 10 lamps would be needed, depending on the size of a display.


Austin, Texas-based Whole Foods Market Inc. already is using fiber optics in some of its seafood departments because of the ice involved.

Paul Ravenelle, director of business development for Solon, Ohio-based Fibertstars, which provided equipment for the independent study, said the Whole Foods store in Oakville, Ontario, was using fiber optics on potatoes before the study was released.

“Anything that is sensitive to the infrared end of the spectrum will be impacted by changing to fiber optic lighting, no question,” said Ravenelle, who added that 99.7% of Fiberstars’ lamps are recyclable.