FDA investigation identified a single supplier of the lettuce, but federal warnings did not name the company

Federal health officials have identified lettuce from Mexico served by Taco Bell locations across five US states as a source of the widespread outbreak of diarrhea-causing parasite cyclospora.

The Centers for Disease Control and Prevention (CDC) late Thursday confirmed the source and warned consumers not to eat shredded iceberg lettuce from Taco Bell restaurants in Indiana, Kentucky, Michigan, Ohio and West Virginia.

A Food and Drug Administration (CDA) investigation identified a single supplier of the lettuce. The federal warnings to consumers did not identify the company.

“FDA is working with the supplier of iceberg lettuce to determine if potentially contaminated shredded iceberg lettuce remains on the market,” including in other states, the CDC said. “Taco Bell has committed to stop using any lettuce from the supplier identified by FDA’s traceback investigation.”

CDC, FDA and public health officials in several states have been investigating a multistate outbreak of cyclospora infections.

More than 30 states have reported infections this year, and current data from them shows the number of infections surpassing the record US mark of about 4,700 set in 2019. The illness is not usually life threatening and is typically treated with antibiotics.

On Tuesday, ahead of the federal government’s confirmation, Taco Bell issued a statement saying it had “voluntarily and temporarily removed limited ingredients at select restaurants as a precautionary measure. We will continue to closely monitor the situation and follow the guidance of public health authorities.”

Cyclospora is a microscopic, spherical parasite that commonly causes watery diarrhea “with frequent and sometimes explosive bowel movements”, according to the US Centers for Disease Control and Prevention. Outbreaks tend to occur most often in the late spring and summer.

The heat-loving parasite infects the bowels and spreads through feces. In the past, people have been infected by consuming fruits or vegetables that were exposed to feces-contaminated irrigation water.

The illness, called cyclosporiasis, is less common than foodborne illnesses caused by other germs, including salmonella and E coli. Many cases are never linked to a specific food or other source and, for years, few US cyclospora outbreaks were reported. But the number started rising about a decade ago, with a particularly notable spike in 2018 and 2019.

Experts say it’s likely that cyclospora cases historically were underreported, in part because some common tests used to check for food poisoning have not been geared to detect cyclospora. They attribute the increasing trend in cases to the climate crisis and better detection.