If the government's final approval last week of low-level irradiation for fruits and vegetables has you eyeing the produce shelves for your first irradiated orange, you may be looking for a long time. The fact is that most of the produce industry is far from ready to use it.

"I think we're years away from any applications," said Wayne Crain, manager of production, marketing and transportation at the Florida Fruit and Vegetable Association. "The proclamation of the regulators is ahead of the research."

There are too many "unknowns," said Crain. Controversy over this technology -- a substitute for chemical fumigants and pesticides using gamma or X-rays that at the approved levels will kill insects and prolong spoilage -- has centered on the safety issue. However, there are many unresolved questions about commercial application, including appropriate dosage levels, handling and shipping procedures, marketing tactics, costs and consumer acceptance, say industry spokesmen.

For the most part, the produce industry doesn't want to be "the guinea pigs," said Sharon Bomer, chairman of the Coalition for Food Irradiation and director of government relations for the United Fresh Fruit and Vegetable Association. In addition, in the midst of a national health-conscious binge over produce, "they don't want to hurt the fresh image" that the industry has established, she said.

Food and Drug Administration spokesman Jim Greene said that it is the agency's job to pass the regulation, and up to the industry to do the practical research for commercialization.

There is still research that must be done, Bomer said. She noted that there are about 10 produce items where the findings on shelf life, taste, aroma and appearance after irradiation have been inconsistent. Apricots, bananas, grapefruits, oranges, pears, pineapples, plums, tangerines, figs and tangelos fit into that category. Sometimes, for instance, a pineapple skin will take on a brownish tinge and the core will turn brown about four days after being irradiated, Bomer said. Other times it won't.

Varieties within a specific category -- such as valencias and navel oranges -- vary in terms of reaction to irradiation and there needs to be more research done on combining irradiation with different shipping temperatures, Bomer said.

In addition, there are some fruits and vegetables that just do not irradiate well, or that actually become more sensitive to spoilage after being irradiated, such as sweet corn, green beans, cucumbers, grapes, lemons, limes, bell peppers and summer squash, Bomer said.

The produce industry realizes that it is "not a be all and end all," said Nancy Tucker of the Produce Marketing Association, but "just another tool."

Tucker said that among the growers who would not be interested in using the technology are those who already run the risk of oversupply, since irradiation can increase shelf life. For instance, this winter there was a large crop of celery and now there is an oversupply of onions, Tucker said. Growers would be working hard to stimulate demand for existing stocks.

John Attaway, scientific research director of the Florida Department of Citrus, said that irradiating Florida citrus would have no immediate usage, either.

For instance, it could potentially open up a major export market to Japan, where the produce is now quarantined because of the fruit fly. Only one part of the problem, however, is that the irradiation response of oranges has been inconsistent; another is that the Japanese have not approved irradiation as a quarantine treatment, Attaway said.

Shipping irradiated Florida oranges to other U.S. states, such as California, Arizona, Texas and part of Louisiana, which also have quarantines of Florida citrus because of the fruit fly, would still not benefit from the FDA approval, Attaway said. Irradiation at the approved dosage level of up to 100 kilorads does not kill citrus canker, so the produce still couldn't be shipped to those states.

Two produce groups that have been waiting in the wings for the approval of irradiation are the papaya and mango growers; in fact, industry spokesmen agree that tropical fruits may get the biggest boost from the technology. Bomer said a "big push" to approve irradiation for produce came last September after the banning of the pesticide ethylene dibromide (EDB). Giving papayas the substitute treatment -- the double-dip hot water method -- does not yield superior quality fruit, said Alan Caldwell, vice chairman of the Coalition for Food Irradiation. However, the U.S. Department of Agriculture, which is in charge of keeping unwanted plant pests and diseases out of this country, still needs to pass its own regulation certifying that the treatment will disinfest the papayas.

Questions still need to be answered, too, about where the irradiation facilities would be located in relation to the growers, the logistics of labeling and who is going to fund all the necessary research. (Caldwell said that major food companies will most likely do the research on how it will fit into their "schemes.")

But "nobody will consider major commercialization until there is consumer acceptance," said Caldwell. Companies must weigh the capital costs of the technology against whether people will actually buy irradiated produce, he said.

While both the pork and seafood industries have conducted marketing studies on consumer reactions to and perceptions of irradiated food, the produce industry has not.

Karen Brown, spokeswoman for the Food Marketing Institute, said that the organization's 1985 trend survey indicated that 70 percent of consumers had not even heard of irradiation, but that that number may have decreased over the past year due to increased publicity about the technology. Brown said that there are a "lot of chicken-and-egg scenarios" -- it is hard to judge consumer acceptance until you roll out the product, and it is hard to know whether to introduce the product until producers know that customers will buy it.

Tucker said that a survey of 15 retailers conducted by the Produce Marketing Association indicated that approximately half of them would not be interested in selling irradiated produce if it had to be labeled, because they felt it would be "the kiss of death."

(The final rule does require that irradiated food be labeled with either "treated with radiation" or "treated by irradiation." The international irradiation logo must also be placed prominently along with the statements.)

Bomer said the United Fresh Fruit and Vegetable Association is having its first seminar about irradiation for its members in May. "Hopefully, the questions will be answered by then," Bomer said. "I doubt it, though."