General Mills is recalling about 600,000 pounds of Gold Medal flour over concerns of E. coli contamination.

The Golden Valley-based food maker issued the voluntary recall Monday after a sampling from its Kansas City facility tested positive for E. coli 026, a potentially deadly strain of the bacteria. No consumers have yet reported illness from eating or handling the flour, according to the U.S. Food and Drug Administration (FDA) announcement.

The recall affects just one date code of 5-pound bags of Gold Medal Unbleached All Purpose Flour. General Mills is urging consumers to check their cupboards and throw away their Gold Medal flour if it's a 5-pound bag labeled with a "better if used by" date of Sept. 6, 2020.

General Mills issued a spate of Gold Medal flour recalls three years ago after two different strains of E. coli, 026 and 0121, sickened dozens of people across more than 20 states. That recall grew to include 45 million pounds of flour, or about 2% of its annual output, which also originated at its Kansas City plant. Producers of bread mixes and other products containing General Mills flour pulled them off shelves, too.

Earlier this year, the company recalled about 100,000 pounds of Gold Medal flour after salmonella was detected in random, on-shelf testing, but no illnesses were reported.

The 2016 recall event raised new questions about the safety of flour and led to public admonitions against eating raw cookie dough and cake batter by the Centers for Disease Control and Prevention and the FDA.

Flour is a raw food product that is not treated to kill potential pathogens and therefore has a greater likelihood than more heavily processed foods of being contaminated in the field or during transportation. E. coli usually originates in feces, such as from livestock. It often reaches humans through raw or undercooked meats but can contaminate crops, like wheat, as well.

"People sort of expect recalls with other types of raw agricultural products, like lettuce or sprouts," said Bill Marler, a national food safety lawyer. "But flour is still such a unique and emerging vector for pathogens that people still scratch their heads."

Food companies and regulators started taking a closer look at flour in 2009 after Nestlé recalled its Toll House cookie dough. Investigators identified flour as the culprit of an E. coli outbreak that sickened more than 70 people, which changed the way the food-safety community thought about flour, said Marler.

General Mills and the FDA remind consumers that E. coli 026 is killed by heat — whether baking, frying, sautéing or boiling products made with flour. Just like with meat, experts said consumers should thoroughly clean countertops, bowls, utensils and hands after coming in contact with flour or dough.

"One reason you don't see a lot of flour outbreaks is because people usually cook it and it's usually not contaminated, or it's contaminated in low quantities," Marler said. "But the public needs to be taught that the way we used flour when we were growing up — like to make play dough or by eating batter — isn't the way we can use it anymore until they come up with some methodology to treat it."

Manufacturers like General Mills usually don't heat-treat their raw flour product before selling it to customers because the process can change its baking properties.

Customers who bought the newly recalled flour can receive a replacement coupon by calling the company at 1-800-230-8103 or visiting GeneralMills.com/flour.