Just days after Global Market News reported that investigators were focusing on shredded iceberg lettuce supplied by Taylor Farms, the U.S. Food and Drug Administration (FDA) has reversed a key finding that had placed the company at the center of the investigation.

The FDA announced Sunday that additional laboratory testing determined the previously reported positive result for cyclospora in a lettuce sample should be classified as a false positive. As a result, the agency now says there are no confirmed positive food sample results tied to the ongoing outbreak.

The development significantly changes the investigation while leaving one major question unanswered: what is actually causing the outbreak that has sickened hundreds of people across multiple states?

FDA Corrects Earlier Test Result

On Saturday, the FDA announced that a sample of shredded iceberg lettuce supplied by Taylor Farms had tested positive for cyclospora, raising concerns that investigators had finally identified the contaminated product.

Less than 24 hours later, the agency withdrew that conclusion.

According to the FDA, laboratory experts conducted additional reviews of the testing data and determined the original result should be considered a false positive.

The agency stated that, as of Sunday, it has no confirmed positive laboratory tests linking any food product to the parasite responsible for the outbreak.

Taylor Farms Says FDA Made a Mistake

Taylor Farms responded quickly after the FDA updated its findings.

The company said regulators informed it that the earlier positive test result was incorrect.

“To be clear, at this moment, FDA has not identified a single positive product test result for cyclospora,” the company said in a statement.

Taylor Farms noted that it voluntarily recalled certain iceberg lettuce sourced from central Mexico after receiving the FDA’s initial notification, describing the action as a precaution taken out of an abundance of caution.

Despite the revised test results, the FDA said it continues working with the company to ensure potentially implicated products have been removed from the marketplace where appropriate.

Taco Bell Outbreak Investigation Continues

While the laboratory finding has changed, the broader outbreak investigation remains active.

Health officials continue investigating a multistate outbreak of cyclosporiasis, an intestinal illness caused by the Cyclospora cayetanensis parasite.

As Global Market News previously reported, investigators have linked many illnesses to shredded iceberg lettuce served at Taco Bell restaurants in:

Indiana
Kentucky
Michigan
Ohio
West Virginia

According to the Centers for Disease Control and Prevention (CDC), the outbreak has resulted in approximately 100 hospitalizations, though no deaths have been reported.

With the FDA now ruling out its only positive food sample, investigators are again searching for the outbreak’s true source.

What This Means for Consumers

The FDA’s latest announcement does not mean the outbreak has ended or that earlier illnesses were misdiagnosed.

Instead, it means investigators no longer have laboratory confirmation connecting Taylor Farms lettuce to the contamination.

Foodborne outbreak investigations frequently evolve as additional laboratory analysis becomes available. Initial findings can be revised when follow-up testing produces different results or identifies potential laboratory errors.

Consumers who experience symptoms consistent with cyclospora infection, including prolonged diarrhea, stomach cramps, nausea, fatigue, or weight loss, should contact a healthcare provider.

What Investors Should Watch

The FDA’s reversal removes immediate pressure from Taylor Farms after the company had briefly become the primary focus of the investigation.

However, the outbreak itself remains unresolved, leaving uncertainty for restaurants, suppliers, and regulators until investigators identify the true source of contamination.

For Taco Bell parent company Yum! Brands (NYSE: YUM), the investigation is likely to remain a closely watched issue until federal health officials determine exactly what caused the outbreak and whether additional recalls or public health actions become necessary.