Nebraska health officials said alfalfa sprouts are the source of a salmonella outbreak that has sickened nearly 24 people in Douglas County in eastern Nebraska and Iowa.

Sun Sprouts are locally grown sprouts distributed by CW Sprouts of Douglas County, Omaha which are sold at grocery stores and restaurants which have been linked to the outbreak. Infected people who were interviewed all had the common link of sprouts which made officials pinpoint them to be the likely cause.

The Nebraska health department as of Tuesday had confirmed 14 cases in Nebraska, eight in Douglas County, four in Sarpy and one each in Cass and Lancaster counties. Four more probable cases have been isolated by officials.

Nebraska's chief medical officer Joann Schaefer said during a Tuesday news conference that there are 8 to 10 more cases of salmonella that are suspected from the same strain.

The Food and Drug Administration is investigating conditions at the company in order to find out how the sprouts got contaminated. The investigators are looking into the possibility that the food may have been contaminated before it reached CW Sprouts as sprouts can be contaminated with salmonella during the growing process, where they can come into contact with fertilizer and humidity.

Officials said CW Sprouts has been cooperative in the investigation process and has voluntarily recalled all of its sprouts. Health officials have asked people to throw away any alfalfa sprouts they may have.

The Iowa Department of Public Health in a news release said five cases had been confirmed and at least four other cases are suspected from the salmonella St. Paul strain. Polly Carver-Kimm, a spokeswoman with the Iowa department said, "They're spread all across the state. The DNA fingerprint of the salmonella is the same as the Nebraska cases, and all of the people involved have similar exposure to alfalfa sprouts."

Schaefer said she did not know whether states other than Nebraska and Iowa had been affected and said the Nebraska cases were reported from Feb. 2 to Feb. 23. The department is working with the Centers For Disease Control and Prevention in containing the outbreak in that state.

The health department recommended consumers wash all fruits and vegetables before consumption, but Schaefer said officials believe the salmonella was probably within the alfalfa sprouts, and therefore, could not be washed off.

"The company does all sorts of washing procedures in its plant," Schaefer said. "It's state of the art. It's probably one of the cleanest facilities we've seen."