Federal officials have closed the book on an outbreak of Salmonella infections among Jimmy John’s customers, saying a specific source could not be identified, even though 80 percent of the sick people ate raw sprouts from the restaurant chain before becoming ill.

Reporting 10 confirmed cases of the outbreak strain of Salmonella Montevideo infections across three states, the Centers for Disease Control and Prevention declared the outbreak over and issued its final report Wednesday. None of the sick people were admitted to a hospital.

Eight of the people who became ill said they ate sprouts on Jimmy John’s sandwiches from restaurants in Wisconsin and Illinois. One person reported eating fresh, raw sprouts from a grocery store in Minnesota. No information was provided on the other person who became ill with the outbreak strain of Salmonella.

A wrap-up statement from the Food and Drug Administration, also released Wednesday, reported the agency could not pinpoint the source of the Salmonella, but that “any contaminated sprouts that made people sick in this outbreak would no longer be on the market.”

“State and local partners, including the Illinois Department of Public Health, Minnesota Department of Health, the Minnesota Department of Agriculture, the Wisconsin Department of Agriculture, Trade and Consumer Protection, and the Wisconsin Department of Health Services, assisted trace back activities in this outbreak by collecting invoices from various Jimmy John’s locations, the Minnesota grocery store and/or distributors to help determine the source of the sprouts,” according to the FDA outbreak investigation update.

“The FDA collected invoices and/or samples from growers and seed suppliers that produced the sprouts. All the samples that were collected subsequently tested negative. The FDA continues to work with these facilities to address potential issues that may have contributed to contamination during production.”

Illnesses started on dates ranging from Dec. 20, 2017, through Jan. 28 this year, according to the CDC. All 10 infected people were women.

The CDC doubled down on its long-time warnings about the dangers of eating raw, fresh sprouts. People who choose to eat sprouts should cook them thoroughly to reduce the risk of illness.

“Regardless of where they are served or sold, raw and lightly cooked sprouts are a known source of foodborne illness and outbreaks,” the CDC advised in the Wednesday outbreak report.

The FDA posted the following timeline detailing the outbreak investigation:

  • CDC notified the FDA of the illnesses on Jan. 16.
  • By Jan. 17 federal and state investigators had received epidemiological information that some ill people reported eating sprouts on sandwiches at multiple Jimmy John’s locations in Illinois and Wisconsin.
  • On Jan. 18 the FDA, CDC and state partners spoke with Jimmy John’s corporate headquarters to learn more about the origin of the clover sprouts.
  • On Jan. 19 the FDA and CDC advised people dining at Jimmy John’s locations in Illinois and Wisconsin to avoid sprouts. On the same day, Jimmy John’s announced that it had directed all of its retail locations to temporarily stop serving sprouts.

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