Two new cases, both from Michigan, have been confirmed in the multistate outbreak of E. coli O26 linked to raw clover sprouts served at Jimmy John’s restaurants in six states, the Centers for Disease Control and Prevention reported Friday.

That brings the outbreak total to 14. All of those sickened are female. Two have been hospitalized.

Both new cases said they ate sprouts at Jimmy John’s restaurants in the week before they became ill.

Iowa has reported five cases tied to the outbreak, Missouri has reported three, while Kansas and Michigan each have reported two cases. Arkansas and Wisconsin each have reported one outbreak-connected case.

The case patients range in age from 9 to 49 years old. The median age is 25. Onset dates of their illnesses range from Dec. 25, 2011 to Feb. 1, 2012.

“Preliminary results of the epidemiologic and traceback investigations indicate eating raw clover sprouts at Jimmy John’s restaurants is the likely cause of this outbreak,” the CDC stated in the investigation update.

The CDC report provided no new information on the Food and Drug Administration traceback investigation.

In its initial report, the CDC said the traceback probe had implicated a common lot of clover seeds used at two separate sprouting facilities. Both growers supplied sprouts to Jimmy John’s restaurants.

The CDC said the seed supplier told the sprouting facilities on Feb. 10, 2012 to stop using the suspect lot of clover seed. 

Many clover seeds are produced for agricultural use, so they might not be processed, handled and stored as human food would, the CDC noted.

Sprout seeds can become contaminated with pathogens if they are grown with contaminated water or improperly composted manure fertilizer. They could also be contaminated with feces from domestic or wild animals, or with runoff from animal production facilities, or by improperly cleaned growing or processing equipment.

Bacteria on the seeds will grow and multiply rapidly in the warm, moist conditions used to sprout the seeds.

Jimmy John’s began serving clover sprouts on its sandwiches last year, after a multistate outbreak of Salmonella was linked to the alfalfa sprouts it used. Last week, a franchise owner  in Missouri said sprouts were being removed from Jimmy John’s menus.

Raw sprouts served at Jimmy John’s restaurants have been tied to five outbreaks in four years.

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CDC Outbreak Map