Update (July 18): Federal investigators have identified Taylor Farms as the supplier of the shredded iceberg lettuce linked to the Taco Bell outbreak. The company has voluntarily recalled affected lettuce sourced from central Mexico, while Taco Bell has removed the ingredient from restaurants as the investigation continues. Federal officials are also investigating lawsuits filed by customers who say they became ill after eating at Taco Bell.

One of America’s largest fast-food chains is facing increased scrutiny as federal and state health officials investigate whether Taco Bell locations may have contributed to a growing outbreak of cyclosporiasis that has sickened more than 2,600 people in Michigan.

The investigation comes as customers at several Detroit-area Taco Bell restaurants reported seeing notices stating that lettuce, cilantro, onions, pico de gallo and guacamole were temporarily unavailable because of what the signs described as a “national recall.”

While no official recall involving Taco Bell has been announced by federal regulators, investigators are examining whether fresh produce supplied to some restaurants may be connected to what has become Michigan’s largest recorded outbreak of the parasite.

Michigan Records Largest Cyclosporiasis Outbreak in State History

According to the Michigan Department of Health and Human Services, more than 2,600 confirmed cases of cyclosporiasis have now been identified, making it the largest outbreak ever recorded in the state and one of the biggest seen nationwide in recent years.

Health officials say the investigation remains active.

In a statement released Monday, the department said current evidence points toward lettuce or other salad greens as the most likely source of the outbreak. However, investigators cautioned that additional foods have not yet been ruled out, and they have not identified any specific grower, supplier or distributor responsible.

No deaths have been reported.

Taco Bell Investigation Continues

According to sources familiar with the investigation who spoke to The Washington Post, both federal and state agencies are reviewing whether Taco Bell restaurants may have played a role in the outbreak.

Neither Taco Bell, its parent company Yum! Brands, the U.S. Food and Drug Administration, nor the Department of Health and Human Services immediately commented on the reports.

Importantly, the FDA has not announced a recall involving Taco Bell, and no public FDA notice currently identifies the restaurant chain as being linked to the outbreak.

The investigation remains focused on determining whether contaminated produce may have entered portions of the restaurant’s supply chain rather than concluding that Taco Bell itself caused the illnesses.

What Is Cyclosporiasis?

Cyclosporiasis is a gastrointestinal illness caused by the microscopic parasite Cyclospora cayetanensis.

People typically become infected after consuming contaminated fresh produce or water. The parasite is most commonly associated with imported fruits and vegetables, particularly leafy greens, cilantro and herbs.

Symptoms can appear several days after exposure and may include:

Severe watery diarrhea
Frequent or “explosive” diarrhea
Loss of appetite
Weight loss
Stomach cramping
Nausea
Fatigue

Without treatment, symptoms can last for several weeks and sometimes return after temporarily improving.

Why Fresh Produce Is Under the Microscope

Unlike many foodborne bacteria, Cyclospora cannot multiply in food after harvest. Instead, contamination typically occurs before produce reaches consumers, often through contaminated irrigation water or unsanitary growing conditions.

Because many fresh vegetables are consumed raw, washing alone may not completely eliminate the parasite.

Investigators are now working to determine whether lettuce or another fresh ingredient distributed through the food supply chain is responsible for the Michigan outbreak.

A Major Brand Faces Questions

Taco Bell serves more than 40 million customers each week across the United States and operates more than 8,700 restaurants worldwide.

The company is owned by Yum! Brands, which also operates KFC, Pizza Hut and The Habit Burger Grill.

At this stage, investigators have not concluded that Taco Bell caused the outbreak, and no specific supplier has been identified. Health officials emphasize that the investigation remains ongoing as they continue tracing the source of the contaminated produce.