Three people have been hospitalized.
The source of the contamination remains unknown.
"The investigation is looking at both food and non-food exposures as part of the ongoing investigation," a CDC statement read. "State public health officials are interviewing ill persons to obtain information regarding foods they might have eaten and other exposures in the week before illness."
Illness onset dates range from April 15 to May 12. Infections that began after May 12 may not have been reported yet. The most recent case was reported on June 4.
A 21-month-old girl in Louisiana died from her infection on May 31 after falling ill several weeks earlier. This outbreak has no connection to the May 26 death of a 6-year-old Massachusetts boy suffering from an E. coli O157:H7 infection.
