Sweet onions are a growth item at the retail level, and their sales can bring sweet returns to retailers and grower-shippers.

But imposters — those labeled as sweet but that are more pungent — can sour consumers and rob retailers of repeat purchases and potential sales increases, said David Burrell, president of the Nation Onion Lab, Collins, Ga.

The onion category overall accounted for about $1.2 billion in retail sales in 2010, not counting club or discount stores, which account for about 20% more, Burrell said.

About 30% of the onion sales were from those labeled sweet.

Although the overall onion category is growing about 3% per year, the sweet onion portion is growing at 7% annually, which says “consumers want sweet onions,” Burrell said.

During the past 10 years, the lab tested more than 20,000 sweet-labeled onions purchased from retailers for pyruvic acid — a major cause of pungency — and brix levels.

More than 50% exceeded what many in the industry consider the pyruvic acid threshold for sweetness — 5 micromoles, Burrell said. Onions testing less than 5 micromoles of pyruvic acid would typically be called sweet.

To help verify sweetness, the lab offers a Pungency Plus certification program. It examines several additional chemical components that contribute to an overall consumer taste, flavor strength, aftertaste and sweetness.

“Onions are extremely complex to test because it’s a reaction that’s occurring,” Burrell said. “The flavor doesn’t actually occur until the tissue is crushed to create an enzymatic action. It’s like measuring a fireworks display.”


Waning interest

However, Burrell said interest in the certification program is waning because retailers and grower-shippers are more focused on costs rather than long-term gains.

“For the retailer, it not only increases the sales — it increases the value,” Burrell said. “If consumers have a good sweet onion experience, they’re going to buy more and be willing to pay a higher price.”

Greencastle, Pa.-based Keystone Fruit Marketing Inc. has the National Onion Lab test all of the sweet onions it markets under its Certified Sweet program, said Dan Borer, general manager of Keystone Northwest.

The produce marketer offers year-round sweet onions from Mexico, Walla Walla, Texas, Georgia and Peru. Only onions that the lab classifies as sweet or extra sweet carry the Certified Sweet label, he said.

Keystone Fruit Marketing continues to educate retailers about how sweet onion certification provides a good eating experience to consumers and promotes return purchases, Borer said.

Saven Corp. Inc., Charleston, W.Va., offers year-round sweet onions under the Oso Sweet label from Northern and Southern Hemisphere growing regions.

The company runs brix and pyruvic acid tests in-house to ensure that onions carrying the Oso Sweet name meet minimum standards, said Mark Breimeister, national sales manager.

But he said not everyone goes to those lengths.

“There are quite a few imposter sweet onions out there,” Breimeister said. “I’d hope that the consumer is becoming more savvy and conscious that we only sell true sweet onions.”