Forty-two years after introducing what grew into an iconic Minnesota State Fair food item, the folks at Original Deep Fried Cheese Curds are calling it quits.

Not to worry: Cheese curds will still be served at other fairgrounds vendors. But Dick and Donna Mueller and Audrey Skarda have decided to retire.

“The three of us, we have to be done,” said Dick Mueller. “We’re all 80 years old, and we can’t be working 16, 18 hours a day.”

The stand is one of four at the fairgrounds selling cheese curds.

“We were the first,” said Dick Mueller. “All the rest have been copycats.”

For those unfamiliar with the dairy delicacy, the version at the Original Deep Fried Cheese Curds stand starts with small pieces of fresh Cheddar cheese from Ellsworth Cooperative Creamery in Ellsworth, Wis. They’re dipped in a batter, deep-fried in soybean oil and served in half-pound portions in paper baskets.

Given their adored status, it’s surprising to learn that cheese curds weren’t an immediate hit.

“It took about three or four years for them to catch on,” Dick Mueller told the Star Tribune in 1996. “But in the last seven or eight years, they’ve sold like crazy.”

They did, indeed. In 1991, the operation hit sales of $263,000 (that’s $463,000 in 2017 dollars), which placed the stand as the fair’s second-highest-grossing food vendor. “We got lucky,” said Dick Mueller.

Their stand remained in the Food Building until 2002, when it was replaced by their Mouth Trap competitors and relocated to a building they built at Dan Patch Avenue and Underwood Street.

In 2016, the stand reported gross sales of $392,000, which represented about 20 percent of all deep-fried curd sales on the fairgrounds.

Dick Mueller said he began thinking about retiring from the fair in 2014.

“We get approached fairly regularly about transferring licensing within families,” said Jerry Hammer, the fair’s general manager. “And most but not all requests are approved. We never got that request from Dick and his family.”

Tom Mueller, Dick and Donna’s son, disputes this account.

“I applied 13 months ago,” he said. He received a “thanks, but no thanks” letter from the fair last week.

“They have the right to do what they want,” said Dick Mueller.

Following fair covenants, the building and its equipment were appraised by a fair-appointed appraiser, and it was purchased by the fair. Hammer said several tenants are looking at the building. This much is certain: The new tenant won’t be frying cheese curds.

“There are a few possibilities that we’re zeroing in on,” he said. “It’s like buying a house. Until you close, and have the keys, nothing is finalized.”

The Muellers and the Skardas raised their kids — and later, their grandchildren — at the stand.

“It was one of the greatest things you could do as a family,” said Dick Mueller. “Working together, sweating together, every year. With 42 years, we’ve got to be a part of Minnesota history.”