General Mills Inc. has initiated a nationwide recall of three brands of flour, totaling about 10 million pounds, in response to a 20-state E. coli outbreak that has sickened 38 people.

“State and federal authorities have been researching 38 occurrences of illnesses across 20 states related to a specific type of E. coli O121, between December 21, 2015, and May 3, 2016,” according to a news release from General Mills.

“While attempting to track the cause of the illness, CDC (Centers for Disease Control and Prevention) found that approximately half of the individuals reported making something homemade with flour at some point prior to becoming ill. Some reported using a General Mills brand of flour.”

The recall includes six SKUs (stock keeping units or UPC codes) of Gold Medal branded flour, two SKU’s of Signature Kitchens branded flour and one SKU of Gold Medal Wondra branded flour.

Retailers that received shipments of the recalled flour include Safeway, Albertsons, Jewel, Shaws, Vons, United, Randalls, and Acme.

“To date, E. coli O121 has not been found in any General Mills flour products or in the flour manufacturing facility, and the company has not been contacted directly by any consumer reporting confirmed illnesses related to these products,” according to the news release.

“As a leading provider of flour for 150 years, we felt it was important to not only recall the product and replace it for consumers if there was any doubt, but also to take this opportunity to remind our consumers how to safely handle flour,” Liz Nordlie, president of General Mills Baking division, said in the release.

Some of the outbreak victims may have eaten raw dough or batter. Nordlie said in the news release and a separate blog posting that no one, especially young children, should ever eat raw dough or batter because of potential pathogens.

“Consumers are reminded to not consume any raw products made with flour. Flour is an ingredient that comes from milling wheat, something grown outdoors that carries with it risks of bacteria which are rendered harmless by baking, frying or boiling,” according to the news release.

“Consumers are reminded to wash their hands, work surfaces, and utensils thoroughly after contact with raw dough products or flour, and to never eat raw dough or batter.”

The recalled flour products can be identified through a link on the General Mills web site.