At least three Colorado residents became ill during the outbreak; all had eaten hamburgers made from Flanders Provision Co. frozen ground beef patties that had been purchased at Wal-Mart, and all tested positive for the same strain of E. coli that had been isolated from case-patients across the country.
Flanders Provision Company expanded its frozen ground beef patty recall to include an additional 184,000 pounds on September 23, 2005.