General Mills has spent tens of millions of dollars at its Fridley flour mill to produce oat flour that's free of gluten.
The company built a seven-story concrete monolith and filled it with expensive machines, all to weed out little bits of wheat, barley and rye — gluten-containing grains that sneak into shipments of oats from the farm.
The effort is critical to producing gluten-free Cheerios, one of General Mills' biggest cereal offensives in recent years. The company also has invested in safeguards at its cereal factories, physically separating gluten-free production.
Yet four months into General Mills' conversion to gluten-free Cheerios, its system failed. The company last week recalled 1.8 million boxes of Cheerios and Honey Nut Cheerios made at a plant in Lodi, Calif., after discovering the cereal accidentally contained wheat.
"They are trying to get off to a good start with these gluten-free products, and you don't want a glitch," said Jack Russo, a stock analyst at Edward Jones.
Cheerios' Facebook page lit up with concerns over the recall. "It's going to be harder than you know to regain our trust," one person wrote. The company apologized on Facebook and on its Taste of General Mills blog, telling Cheerios fans it was "embarrassed."
Gluten-free products are one of the hottest trends in the food industry, and General Mills is counting on them to help revive stagnant cereal sales. But making the nation's largest cereal brand gluten-free is a daunting engineering task.
"In one way, I was surprised about [the recall], and in another way I wasn't," said Jon Faubion, a grain science professor at Kansas State University. General Mills "is really committed to this and it has put a lot of time and money into it. But I'm not surprised just given the huge challenge."