(June 12) There’s more than one way to ripen fruits and vegetables.

But many people in the business don’t know the best way, said Dennis Kihlstadius.

Kihlstadius, president of Produce Technical Services, Bemidji, Minn., and a consultant to the California Pear Advisory Board, Sacramento, spoke at a May seminar on ripening at the University of California-Davis’s Postharvest Technology Research & Information Center.

One of the themes that emerged from the seminar, Kihlstadius said, was the need to correct misconceptions about ripening and to educate industry members on the subject.

The most important ingredient in successful ripening is ethylene, Kihlstadius said. While most people in the business probably know that bananas depend on ethylene, it may not be as well-known that all fruits and vegetables that need ripening should be treated with the gas.

Take stone fruit, for instance, Kihlstadius said. When a lot of people in the business talk about preconditioning pears, they mean treating them with heat. When Kihlstadius talks about preconditioning, he means a process centered around exposure to ethylene.

Kihlstadius also finds he needs to educate people on the proper amount of ethylene to use. Many use too much. The proper amount, depending on the fruit or vegetable being ripened, is with 50-150 ethylene parts per million, he said.


A misconception about ripening that Kihlstadius hopes to clear up concerns an all-natural approach. Many fruits advertise themselves as “tree-ripened.” While that’s well and good for some, it’s not the case for all.

Take pears. When pears are left on trees too long to ripen, they turn woody, Kihlstadius said.

Kihlstadius said that while more companies are beginning to invest in properly designed ripening rooms, many don’t adequately educate their employees on how to use them. He likened it to a general who gives his soldiers their orders, then fails to check up on them once they’re on the battlefield.

A new product from Catalytic Generators LLC, Norfolk, Va., helps ensure that those expensive ripening facilities are properly used once they’re built. In late 2005, the company introduced Smart-Ripe, an ethylene generator equipped with a microprocessor that lets workers track the heat and humidity in ripening rooms.

Every five minutes, updated readings get posted to the company’s Web site, which customers can access, said Greg Akins, president and chief executive officer.

“A lot of guys don’t monitor humidity and heat the way they should,” he said. “This helps them be more efficient.”