( CNN ) -- A salmonella outbreak linked to alfalfa sprouts has sickened 89 people in 15 states and the District of Columbia , the Centers for Disease Control and Prevention reported Thursday . About 23 % of those sickened were hospitalized , but no deaths have been reported , according to the CDC . Health officials say the first cases identified date to November 1 . The preliminary investigation shows a possible link to alfalfa sprouts . `` Preliminary results of this investigation indicate a link to eating alfalfa sprouts at a national sandwich chain , '' the CDC said in a statement . In Illinois , where the bulk of cases have been identified , the state Department of Public Health says many of 50 sickened residents reported eating alfalfa sprouts at locations of Jimmy John 's . The founder of Jimmy John 's said test results of sprouts from its main supplier tested negative . In a letter sent to all Jimmy John 's franchises , founder Jimmy John Liautaud said store locations have all come up negative for the bacteria as well . `` As a goodfaith and goodwill gesture I am asking Illinois stores to pull sprouts until the state can give us some better direction , '' the letter states . `` We are working closely with the state and they are doing a darn good job in helping find the source . Again , no source has been found yet , this is a precautionary measure . '' According to the CDC , Illinois has 50 cases , Missouri reports 14 cases , Indiana reports 9 , Wisconsin has three and Pennsylvania reports two . Connecticut , Georgia , Hawaii , Iowa , Massachusetts , New York , South Dakota , Tennessee , Texas , Virginia and the District of Columbia all have one confirmed case . The CDC is working with the Food and Drug Administration and state public health departments to investigate this outbreak . Health officials have identified the particular strain of salmonella through diagnostic testing . The strain has been identified as Salmonella serotype I 4 , [ 5 ] ,12 : i : - . This is a common type of salmonella , says Chris Braden , a physician and director of the CDC 's Division of Foodborne , Waterborne and Environmental Diseases . `` Alfalfa sprouts have been associated with a number of outbreaks '' Braden adds . The FDA and state health departments will be investigating the sprout growers , as well as the seed suppliers , in an effort to find the source the outbreak , Braden said . `` The FDA is aware of the situation and is working with the CDC to determine the cause of the illnesses , '' Michael Herndon , a FDA spokesman , confirmed Thursday . `` As more information becomes available we will alert the public . '' Salmonella is a bacterial infection that usually last four to seven days . The infected person develops fever , abdominal cramps and diarrhea between 12 and 72 hours after becoming infected . Most people recover without treatment . Very young and very old people , as well as those with weakened immune systems , can suffer severe illness and , in the worst cases , possibly death , according to the CDC . About 40,000 cases of salmonella are reported each year in the United States , the agency said . The CDC recommends anyone suspecting he or she may be ill from eating contaminated food should talk to their doctor . Pregnant women , children and the elderly should avoid eating all raw or undercooked sprouts , the CDC suggests . The only way the bacteria can be killed is by thoroughly cooking the sprouts .
CDC says 89 people have been sickened . Sandwich chain part of investigation . Comment: Still , Illinois stores pull sprouts from menu .