Update: FDA continues to investigate source of cyclosporiasis outbreak

LATEST UPDATE: Tuesday, July 21, at 12:48 PM EST

The Food and Drug Administration (FDA) is still looking into Taylor Farms de Mexico as the source of a nationwide cyclosporiasis outbreak. Despite a previous test identifying the parasite in a sample of lettuce sold by the food supplier, the government agency said Sunday that the assessment should be disregarded.

"Due to the complexity in detection of Cyclospora, FDA laboratory experts re-reviewed the sample results and have concluded that the finding does not represent true amplification and should be considered a false positive," the FDA stated in its latest update.

Taylor Farms has announced a voluntary recall of all iceberg lettuce sourced from central Mexico. This includes market-side-brand products available at Walmart, described as “Iceberg Salad 12-oz or 24-oz” and “Shredded Lettuce 8-oz or 16-oz,” with Best if Used By dates of 7/18/2026 to 8/3/2026 and July 18 to August 3, 2026, respectively. Other recalled products were distributed to food service customers. 

The FDA is still urging consumers not to eat the brand's iceberg lettuce, while Taco Bell has announced it is no longer using the product. The company also provided a timeline fact-checking the events, along with a statement regarding the false positive.

"We are no longer sourcing iceberg lettuce grown in central Mexico for the remainder of the growing season," the July 20 update reads.

A complete list of recalled products is available here.

The Food and Drug Administration (FDA), along with the Centers for Disease Control and Prevention (CDC), might have found the source of the cyclospora outbreak sweeping the nation.

On July 16, following an investigation that is still ongoing, the government agencies announced that the source of the infection can be traced back to products purchased at Taco Bell stores in Indiana, Michigan, Kentucky, Ohio, and West Virginia. All patients who reported eating at one of the chain's stores had meals that included shredded iceberg lettuce sourced from a single Mexican supplier identified by the authorities. 

According to the FDA and CDC's latest update on the outbreak, Taco Bell is working with the agencies to stop the use of all lettuce implicated in the outbreak. The Mexican supplier is also cooperating with the authorities in ensuring that all potentially implicated products are removed from the market. 

The notice was clear in that not all Taco Bell stores in the mentioned states were supplied by the same Mexican distributor. However, the agencies also said that more states, brands, restaurants, retailers, and distribution channels may be added to the advisory as the investigation continues. 

Over 1,600 cases nationwide

Cyclosporiasis, the intestinal illness resulting from the Cyclospora parasite, is highly seasonal in the US and peaks during the spring and summer, when consumer demand for fresh items like basil, cilantro, spinach, and berries (the pathogen's main vector) spikes. 

Source: CDC

Patients experience a range of GI symptoms, including cramps, nausea, fatigue, loss of appetite, low-grade fever, and vomiting. According to the CDC, the most commonly reported symptom is “watery diarrhea with frequent and sometimes explosive bowel movements.” Symptoms can take anywhere from two days to two weeks to appear after exposure.

To date, the FDA and CDC have officially reported 1,644 cases in five states, along with 94 hospitalizations and zero deaths. The federal authorities have clarified that their numbers may differ from those of local health departments, as "state data may include both probable and confirmed cases, while CDC and FDA include confirmed cases only."

Outbreak prevention recommendations

As the investigation continues, government agencies recommend that the public not eat food items containing shredded iceberg lettuce from Mexico served at Taco Bell locations in Indiana, Kentucky, Michigan, Ohio, and West Virginia.

"If you have symptoms of cyclosporiasis, contact your health care provider to report symptoms and receive care, especially if you ate shredded iceberg lettuce in the two weeks before you got sick," the update reads. "If you purchased or received food items with shredded iceberg lettuce served at Taco Bell at one of these locations, carefully clean and sanitize any surfaces or containers that it touched."

*All images are referential via Shutterstock unless stated otherwise.

Related stories

Parasite outbreak puts US health agencies on fruit alert as industry pushes back