A recent salmonella outbreak in Minnesota that’s sickened 64 people and hospitalized nine has now been traced back to tomatoes that were served at 22 Chipotle restaurants in the state, prompting the chain to switch tomato suppliers.

Investigators from the Minnesota Department of Health, the Minnesota Department of Agriculture and the U.S. Food and Drug Administration are now working to trace the tomatoes back to the farm of origin, the MDH said in a press release.

Customers eating at the chain going forward aren’t at risk, as Chipotle has now switched tomato suppliers and none of the product remains in stores, but MDH says more illnesses could still be reported.

“We expected to see additional cases because it can take up to 10 days for symptoms of Salmonella to appear, another few days to a week before people go to their doctors and the cases get reported to us,” said MDH Epidemiologist Dana Eikmeier. “However, there is no longer a risk of Salmonella from this particular product at Chipotle.”

Those who were sickened said they’d eaten at one of 22 Chipotle restaurants in the state between Aug. 16-28, and fell ill between Aug. 19-Sept. 3.

Click here for MDH’s list of Chipotle locations linked to the outbreak to date.

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