Mexico’s health minister said Tuesday that officials have not found evidence that Mexican lettuce caused a U.S. cyclospora outbreak. The statement came as U.S. health agencies continue to point to shredded iceberg lettuce from Taylor Farms de Mexico in their investigation.

The outbreak has been linked to lettuce served at some Taco Bell locations in Indiana, Kentucky, Michigan, Ohio and West Virginia. U.S. officials say the investigation remains open.

Mexico Questions Lettuce Link in Cyclospora Outbreak

Mexican Health Minister David Kershenobich said there is no evidence so far that the outbreak originated in Guanajuato, where Taylor Farms de Mexico operates.

“So far, no evidence has been found to indicate that it originated there,” Kershenobich said Tuesday, according to Reuters. He added that Mexican officials are still taking precautions.

Mexico’s sanitary regulator, Cofepris, and agricultural safety agency, Senasica, are reviewing the issue. Reuters reported that the agencies are conducting preventive inspections and traceability checks.

Mexican officials have also said only three Cyclospora cases have been confirmed in Mexico. They said those cases do not indicate a local outbreak.

FDA Still Warns Against Recalled Lettuce

The U.S. Food and Drug Administration says its traceback investigation still points to shredded iceberg lettuce from Taylor Farms de Mexico. The FDA said the lettuce was used at Taco Bell locations where people ate before becoming sick.

However, the case has become more complicated. The FDA first reported a positive Cyclospora test from a Taylor Farms lettuce sample. The agency later said that result was a false positive after a review by laboratory experts.

As of July 19, the FDA said there were no confirmed positive product test results for Cyclospora. Even so, the agency said its investigation remains active.

Taylor Farms de Mexico recalled all iceberg lettuce sourced from central Mexico on July 17. The recall includes products sent to restaurants, food service customers and some retail stores.

Illnesses Reported in Five States

The CDC says more than 1,644 people have been infected in the five-state outbreak. The agency reported 94 hospitalizations and no deaths.

Symptoms of cyclosporiasis can include watery diarrhea, fatigue, loss of appetite, stomach cramps, bloating and nausea. Symptoms often begin about one week after infection.

The CDC says people may need to ask specifically for Cyclospora testing. Routine stool tests do not always check for the parasite.

Health officials advise consumers not to eat recalled iceberg lettuce from Taylor Farms de Mexico. The CDC also recommends throwing away recalled lettuce or returning it to the store.

Texas Products Included in Recall

No Texas cases are included in the five-state outbreak count listed by the CDC and FDA. However, the FDA says recalled products were distributed to Texas and several other states.

Recalled Marketside-brand iceberg products were sold at select Walmart stores in Texas and 14 other states. Other recalled products went to food service customers in 27 states.

Consumers, restaurants and retailers should check product lists from the FDA recall notice. Any surfaces or containers that touched recalled lettuce should be washed and sanitized.

The FDA says Taco Bell stopped using lettuce from Taylor Farms de Mexico as of July 17.

What Consumers Should Know

Cyclospora spreads through food or water contaminated with the parasite. Washing produce can reduce risk, but it may not remove all contamination.

The CDC says cooking produce to at least 158 degrees can kill the parasite. Anyone with prolonged diarrhea or related symptoms should contact a health care provider.

For now, Mexico says there is no proof its lettuce caused the outbreak. U.S. agencies say the recalled lettuce remains the focus of the investigation. Consumers should follow recall guidance while officials review the source and scope of the contamination.