The number of cases in the E. coli outbreak linked to McDonald's Quarter Pounders has risen to 90, federal health officials said in an update on Wednesday.

Cases have been reported in 13 states, according to the Centers for Disease Control and Prevention (CDC).

Most of the cases have been in Colorado, which has 29 reported cases, and Montana, which has 17 reported cases, according to the CDC.

Cases have also been reported in Iowa, Kansas, Michigan, Missouri, Nebraska, New Mexico, Oregon, Utah, Washington, Wisconsin and Wyoming, according to the CDC, which further notes that illnesses have occurred between Sept. 27 and Oct. 16 of this year.

This is a developing story. Please check back for updates.