Cyclospora Outbreak Investigation Update: FDA Says Lettuce Test Linking Taylor Farms Was a False Positive

A laboratory test that appeared to identify the source of a major Cyclospora outbreak in the United States has been ruled a false positive, according to health officials. The US Food and Drug Administration (FDA) confirmed that further review of an iceberg lettuce sample linked to food supplier Taylor Farms did not show a true detection of the parasite responsible for the outbreak.

The development means investigators still do not know the exact source of the Cyclospora contamination that has affected thousands of people across several US states. Health agencies continue working to identify the origin of the outbreak while companies and restaurants remove potentially affected products from circulation.

FDA Corrects Earlier Positive Test Result

The investigation gained attention after the FDA announced that a sample of iceberg lettuce from Taylor Farms had tested positive for Cyclospora. Taylor Farms supplies lettuce products to several food businesses, including the Taco Bell restaurant chain.

However, after additional laboratory analysis, the FDA changed its conclusion. Officials said the original result was a false positive caused by the complexity involved in detecting Cyclospora.

The agency explained that laboratory experts reviewed the sample again and determined that the result did not represent a genuine detection of the parasite. The FDA informed Taylor Farms about the updated findings and said it would continue cooperating with the company to make sure any products connected to the outbreak were removed from the market.

Because the test result was incorrect, health officials have not yet identified the true source of contamination.

What Is Cyclospora and Why Is It a Concern?

Cyclospora is a parasite that can cause a foodborne illness called cyclosporiasis. The infection affects the digestive system and is often linked to contaminated food or water.

People infected with Cyclospora commonly experience symptoms such as:

• Persistent watery diarrhoea
• Loss of appetite
• Weight loss
• Stomach cramps
• Fatigue
• Nausea and digestive discomfort

Symptoms may not appear immediately. In many cases, signs of infection can develop around one to two weeks after exposure.

Although Cyclospora infections can be serious and uncomfortable, no deaths have been reported during this outbreak. However, health officials confirmed that at least 94 people have required hospital treatment.

Taco Bell Lettuce Investigation

The outbreak investigation focused attention on shredded iceberg lettuce served at Taco Bell restaurants in several states. The Centers for Disease Control and Prevention (CDC) advised customers not to eat shredded iceberg lettuce from Taco Bell locations in Indiana, Kentucky, Michigan, Ohio, and West Virginia while the investigation continued.

Taco Bell stated that it had completed the removal of affected Taylor Farms lettuce from its restaurants.

The restaurant chain’s response was part of a wider effort to prevent additional infections while officials worked to determine the source of the contamination.

Taylor Farms Takes Preventive Action

Taylor Farms responded to the investigation by voluntarily removing iceberg lettuce sourced from central Mexico from the US market. The company also provided information about affected products and said it was cooperating with government agencies.

The company stated that it had stopped receiving products from the suspected lot, paused distribution of iceberg lettuce from central Mexico, informed customers, and continued working with the FDA, CDC, and state health authorities.

The lettuce removal affected multiple states and included some Marketside-branded iceberg lettuce products sold at Walmart locations in several areas.

Difference Between a Recall and Voluntary Product Removal

During food safety investigations, companies may take action before officials confirm a final source of contamination. A voluntary product removal allows a company to remove products as a precaution.

A formal recall is different. A recall requires a company to notify customers, recover affected products, and follow regulatory procedures.

The FDA explained that the lettuce action involved voluntary removal rather than a confirmed recall process at certain stages of the investigation.

Why Finding the Source Is Difficult

Identifying the cause of a Cyclospora outbreak can be challenging. Unlike some bacteria that can be detected more easily, Cyclospora requires specialized testing methods.

The parasite may also be difficult to trace because symptoms can appear days or weeks after exposure. This makes it harder for investigators to determine exactly where contamination occurred and which food product was responsible.

Food safety experts often examine supply chains, imported products, restaurant records, and laboratory samples when investigating outbreaks. Even with advanced technology, identifying the source may take considerable time.

Current Health Advice

Health officials continue advising consumers to follow updates from the FDA and CDC. People who develop symptoms consistent with cyclosporiasis after eating potentially affected foods should contact a healthcare professional.

Consumers should also practice safe food handling habits, including washing fresh produce when appropriate, keeping food preparation areas clean, and following official recall announcements.

Investigation Continues

The false-positive laboratory result has changed the direction of the investigation but has not ended efforts to identify the cause of the outbreak. The FDA, CDC, and state health departments continue reviewing available information and monitoring cases.

Thousands of infections connected to the outbreak highlight the importance of accurate laboratory testing and rapid communication between government agencies, food suppliers, restaurants, and consumers.

For now, officials have confirmed that the Taylor Farms lettuce sample originally reported as positive for Cyclospora was not the source. The search for the true origin of the outbreak remains ongoing.

Source Note

The US Food and Drug Administration (FDA), Centers for Disease Control and Prevention (CDC), and statements from Taylor Farms regarding the Cyclospora outbreak investigation.

Disclaimer

This article is for informational purposes only and does not provide medical advice. Readers should follow official guidance from health authorities regarding food safety, recalls, and illness prevention.