General Mills has again expanded its flour recall to include additional production dates after the CDC confirmed four more illnesses linked with consuming food containing raw flour contaminated with E. coli.

The recall includes Gold Medal, Wondra and Signature Kitchens brand products. General Mills first issued a recall in May for approximately 10 million pounds of flour. Previously announced recalled flour production dates ranged from Nov. 4, 2015 through Dec. 4, 2015. The expansion includes select production dates through Feb. 10.

The addition of new flour production dates is the result of General Mills conducting proactive flour testing and new information from health officials who are using new whole genome sequencing techniques to trace illnesses. The company says E.coli has been detected in a small number of General Mills flour samples, and some have been linked to new patient illnesses that fell outside of the previously recalled dates.

“At this time, it is unknown if we are experiencing a higher prevalence of E.coli in flour than normal, if this is an issue isolated to General Mills’ flour or if this is an issue across the flour industry,” the company says. “The newer detection and genome sequencing tools are also possibly making a connection to flour that may have always existed at these levels.”

State and federal authorities have been researching 46 occurrences of illnesses across 21 states related to a specific type of E. coli (E. coli O121) between Dec. 21, 2015 and June 25. According to the CDC, investigators determined flour produced at the General Mills facility in Kansas City, MO is a likely source of the outbreak. Since the outbreak, FDA launched a consumer awareness campaign detailing the dangers of ingesting raw dough.

Flour is a raw ingredient that is intended to be cooked or baked. Flour is made from wheat that is grown outdoors where bacteria are often present, and the normal flour milling process does not remove these bacteria.

According to General Mills, in order for severe E. coli illness to occur from flour, all three of the following things have to happen:

• The flour a consumer is using has to contain the rare sub-types of E.coli that can make people sick.
• The consumer has to eat raw dough, batter or other uncooked food made with the flour, or handle the raw dough and not wash his or her hands.
• The consumer’s individual health characteristics will impact if he or she  gets sick and how severely. Some consumers have mild symptoms, and others get very sick. It is not always known who will get sick and who will not.