Fresh basil served by three restaurants has sickened 35 Minnesotans, part of a wider outbreak of contaminated food that sickened people in nearly a dozen states.

Laboratory-confirmed cases have been linked to establishments in Rochester, Hermantown and Duluth, according to the Minnesota Department of Health.

So far 132 people across 11 states have been affected. Four people have been hospitalized, but none in Minnesota.

The basil, imported from Mexico, was contaminated with cyclospora, a microscopic parasite that causes diarrhea, loss of appetite, nausea, fatigue and other food poisoning symptoms.

State disease detectives traced the infections to meals eaten in mid- to late June, according to Doug Schultz at the Health Department, with symptoms appearing until early July.

Cyclospora symptoms typically appear within a week of eating the infected product, but sometimes they can appear up to two weeks out. The long duration can make it hard for investigators to pinpoint the source of the intestinal parasite.

Health officials are hopeful the outbreak has passed.

"We are about a month out from our last [infected] meal date so that is further evidence that there is no ongoing risk at the restaurants at least," said Schultz.

The restaurants include City Market in Rochester, which had 26 cases, Outback Steakhouse in Hermantown, with four cases, and five cases from meals catered by the Duluth Grill for a conference in Duluth.

David Currie, one of the City Market owners, said his restaurant is diligent about food safety but was unfortunate to receive a shipment of infected basil.

"There's nothing we could have done to prevent this other than better luck," he said, noting that washing the basil does not remove the parasite.

"We've switched the supplier that the basil comes through," Currie said. He said he wasn't aware of any problems until being contacted by the local health department.

The Food and Drug Administration said the basil came from the export supplier Siga Logistics de RL de CV, located in Morelos, Mexico.

"Do not consume or serve uncooked items like pesto or salad, that may include fresh basil from Mexico, unless you are certain that the fresh basil was not exported by Siga Logistics de RL de CV," the FDA said in a warning to consumers and restaurants.

As in most foodborne outbreaks, there are likely more cases than those confirmed by laboratory tests. Anyone with symptoms is urged to contact their health care provider and to call the state's foodborne illness hotline at 877-366-3455.

Ryan Osterholm, a food safety lawyer at Pritzker Hageman in Minneapolis, said the infections are a "growing and concerning problem."

"Last year was the biggest year when we represented over 200 people with cyclospora, and this year we may surpass that," he said.

Food products can change hands five to six times between farm and fork, he said. Restaurants and stores should only deal with suppliers that know to avoid products from risky areas. "It is in everybody's best interests to get to the bottom of this," he said.

Nationwide, there have been 580 laboratory-confirmed cases of cyclospora infections since the beginning of May, according to the U.S. Centers for Disease Control and Prevention.

In addition to the outbreak announced this week, health officials are conducting investigations into other clusters related to restaurants.

In 2018, one large cyclospora outbreak sickened at least 250 people who ate prepackaged Del Monte Fresh Produce vegetable trays sold at Kwik Trip stores, including in Minnesota and Wisconsin. Another outbreak affected more than 500 people who ate salads sold at McDonald's restaurants in the Midwest.

Glenn Howatt • 612-673-7192