“Down with the imposters!” has become the battle cry of Peruvian sweet onion shippers.

Tired of seeing onions of every shape, color and pungency stickered as sweet and sold for a premium on retail shelves, importers are fighting back by having their products certified and demanding a standard that everyone must follow.

But who decides what’s sweet? Much less what that standard should be for an industry worth an estimated $425 million and that’s growing 7% each year?

Margret DeBruyn, president of Zeeland, Mich.-based DeBruyn Produce Co., echoes the frustration of many grower-shippers.

“When I’ve put in all the expense to do it the right way, and somebody comes in the back door with perhaps a U.S. onion that doesn’t have the appropriate sweetness certification, it really undermines the purity of the Peruvian market,” she said.

“It hurts everyone.”

Barry Rogers, president of Melbourne, Fla.-based Sweet Onion Trading, in the spring raised the need for a sweet onion standard. He’s still waiting for a meeting with lawmakers to discuss the issue.

“Florida citrus has a sugar standard, and most fruits and vegetables have standards, so why shouldn’t there be a taste standard for onions beyond the Vidalia?” Rogers said.

A number of grower-shippers, including Sweet Onion Trading and Greencastle, Pa.,-based giant Keystone Fruit Marketing Inc., have selected National Onion Labs Inc. of Collins, Ga., to certify their sweet onions, starting in the fields of Peru, which they say helps farmers improve the quality of their crop.

These companies also have adopted NOL’s definition: “A sweet onion, when eaten raw, should have a mild and pleasant flavor that leaves an impression of sweetness and be free from off flavors.”

Rather than simply testing for pungency, which he says does not guarantee sweetness, NOL’s president David Burrell tests for the four qualities that consumers look for in a sweet onion: heat, flavor strength, aftertaste and sweetness.

“If you’re not testing, how do you know if your onions are sweet?” said Burrell, who uses rules and standards set by the Georgia Department of Agriculture in his certification work around the world.

“You just can’t show up to the Indy 500 ... with a bunch of money and say you’re going to put my Volkswagen Beetle in,” he said. “You have to have qualifying trials.

“There needs to be competition, but it needs to be among appropriately qualified product.”

Not all growers, however, are ready to put their faith in a single lab.

Michael Hively, general manager of Glennville, Ga.-based Bland Farms LLC, said a sweet onion standard won’t work unless the certifiers are certified, too.

“Right now, there’s no standard out there,” said Hively.

“You and I could open a lab tomorrow for certifying onions, and who’s going to certify the validity of the data? It would most certainly add costs to the system.”

Hively said Bland uses a third party to test the pungency of its onions in Peru and also tests in-house.

“If you set a standard, you have to have a group of people doing the work and a group of people monitoring,” said Richard Pazderski, Bland’s sales and marketing manager.

The company has never had a sweetness issue with its Peruvian onions, Pazderski said.

Idaho Falls, Idaho-based Wada Farms Marketing Group’s Peruvian growers are certified sweet, said John Vlahandreas, national onion sales director.

But he would welcome an industrywide standard, he said.

“Anyone can put a test kit on an onion and come back with the right peruvic acid number or whatever they’re basing it on, and they’ve got a sweet onion,” Vlahandreas said.

Mark Breimeister, national sales manager for Waterford, Mich.-based Saven Inc., which tests its Peruvian Oso Sweets through Texas A&M University labs, said current testing methods don’t give retailers a consistent product.

“You can get an onion that tests great but doesn’t taste right,” said Breimeister. “That’s the biggest challenge out there.”

He said shippers need to be diligent and not market “fake” sweet onions, while retailers shouldn’t buy an onion that tests well but tastes bad.

“Unfortunately,” he said, “I don’t think we’ve got a real test yet.”