A Salmonella Muenchen outbreak linked to fresh alfalfa sprouts from a Kansas grower now includes 13 people from four states, spurring federal officials to join the investigation. Five of the sick people have required hospitalization, according to the Centers for Disease Control and Prevention, which posted its first report on the outbreak today. Late last week, Sweetwater Farms LLC in Inman, KS, recalled a single lot of its fresh alfalfa sprouts — lot 042016 — according to a Feb. 19 public warning from the Kansas Department of Health and Environment (KDHE). Initial tests at Sweetwater Farms found Salmonella in irrigation water and on alfalfa sprouts at the growing operation, state and federal health officials reported. Follow-up tests results to determine the specific strain of Salmonella are pending, according to the CDC. It is not known if Sweetwater Farms is continuing to grow and ship sprouts while state and federal officials investigate the outbreak. Company officials have not responded to requests for comment. Traceback investigation so far has revealed that the implicated sprouts were sold at retail and distributed to restaurants. However, neither the Kansas warning nor the CDC report provided details on whether the sprouts were distributed outside of Kansas. As of today, the CDC is reporting outbreak victims in the following states: Kansas five cases, Missouri three cases, Oklahoma three cases and Pennsylvania two cases. Illness onset dates range from Dec. 1, 2015, through Jan. 21. Additional cases may have been confirmed, but it can take two to four weeks for the information to be reported to the CDC. Of the 12 outbreak victims who have been interviewed by health officials, 10 reported they ate or may have eaten fresh sprouts before becoming ill. Nine of them reported eating alfalfa sprouts, specifically. Outbreak victims reported eating sprouts at five different restaurants supplied by Sweetwater Farms before becoming ill. Another victim who reported eating the sprouts before becoming ill said the Sweetwater Farms sprouts were purchased at a retail store. Most people infected with Salmonella develop diarrhea, fever, and abdominal cramps between 12 and 72 hours after infection, according to the CDC. In some cases, diarrhea may be so severe that the patient needs to be hospitalized. In these patients, the Salmonella infection may spread from the intestines to the blood stream, and then to other body sites. In these cases, Salmonella can cause death unless the person is treated promptly with antibiotics. The elderly, infants, and those with impaired immune systems are more likely to have a severe illness (To sign up for a free subscription to Food Safety News, click here.)