The FDA has reversed its own laboratory finding, declaring that a test showing Cyclospora contamination in Taylor Farms lettuce from Mexico was a false positive, even as the parasite outbreak it was tied to continues to sicken thousands across the United States.
The correction, posted July 19, 2026, does not end the investigation. The agency said its experts re-reviewed the sample and concluded the result did not represent true amplification of the parasite. Taylor Farms, meanwhile, is still recalling shredded iceberg lettuce and salad kits distributed nationwide, and health officials say the outbreak is far larger than the single supply chain first implicated.
What the FDA Actually Said
The Food and Drug Administration’s original announcement had linked Taylor Farms lettuce grown in central Mexico to the Cyclospora outbreak. That linkage drove the recall. The agency now says the laboratory signal was not reliable.
“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 wrote in its outbreak update.
The retraction raises uncomfortable questions about how regulators confirm contamination in perishable foods. Cyclospora, a microscopic parasite, is notoriously difficult to detect in produce samples, and false positives can trigger costly recalls while false negatives can allow tainted product to reach consumers. The FDA did not say whether a new confirmatory method would be used going forward.
The Recall Stands
Despite the false positive, Taylor Fresh Foods is not pulling back its recall. The company’s recalled iceberg lettuce — all sourced from central Mexico for the U.S. market — remains off shelves and out of food service channels.
Consumer products under recall include Marketside-brand items sold at Walmart: 12-oz and 24-oz Iceberg Salad, and 8-oz and 16-oz Shredded Lettuce, all with Best if Used By dates from July 18 through Aug. 3, 2026. The long shelf life means product purchased weeks ago may still sit in home refrigerators.
On the food service side, Taylor Farms distributed recalled iceberg to Sysco Foods — the largest U.S. food service supplier — and to other customers between June 29 and July 16 across 27 states: AL, AR, CT, FL, GA, IA, IL, IN, KS, KY, LA, MA, MD, MI, MO, MS, NC, NH, NJ, OH, OK, PA, SC, TN, TX, VA, and WI.
Marketside products reached Walmart stores in 15 states: AL, AR, FL, GA, IN, KS, KY, LA, MO, MS, OK, TN, TX, VA, and WV. Taco Bell locations in at least Indiana, Kentucky, Michigan, Ohio, and West Virginia received the recalled lettuce; the chain says it has stopped using lettuce from the Taylor Farms Mexico operation. Taylor Farms has not disclosed which other restaurant chains were supplied.
Outbreak Numbers Far Outpace the Recall
The scope of illness dwarfs the recall footprint. Michigan alone reported 5,002 patients with 102 hospitalizations as of July 17 — a staggering figure for a state that typically records 40 to 50 confirmed Cyclospora cases by this point in the year.
Other affected states show similar surges. Ohio has reported more than 1,240 cases, Indiana more than 320, Kentucky more than 190, and West Virginia 139. The CDC’s own tally as of July 17 was only 1,644 infections tied to Taco Bell exposure across five states, with illness onset dates ranging from May 13 to July 13.
The CDC is now investigating Cyclospora infections across 34 states and says there is likely more than one outbreak underway, with 5,100 additional illnesses under review. The gap between state and federal counts is partly explained by a policy shift: the CDC stopped tracking Cyclospora and seven other foodborne pathogens on July 1, 2025, leaving states to carry the surveillance load.
Why a False Positive Matters
A false positive on a foodborne parasite test is not a minor laboratory footnote. It can misdirect an investigation, consume regulatory resources, and impose heavy costs on growers and distributors whose product may be safe. At the same time, the outbreak is real — thousands are sick — and pinning the source matters for preventing further infections.
The FDA’s retraction leaves the outbreak investigation without its clearest single-source lead. If the Taylor Farms lettuce was not contaminated, investigators must now determine whether another grower, shipper, or distribution path introduced the parasite. Cyclospora outbreaks in the U.S. have historically been linked to imported fresh produce, including cilantro, basil, raspberries, and salad greens.
For consumers, the practical guidance is unchanged. Recalled product should be discarded or returned. Anyone who has eaten recalled lettuce and develops symptoms should seek medical care, because Cyclospora infection requires specific diagnostic testing and antibiotic treatment — it does not resolve reliably on its own.
Symptoms and Risk
Cyclospora infection causes severe, watery and often explosive diarrhea that can last a month or longer without treatment. Additional symptoms include abdominal pain, nausea, vomiting, body aches, and fatigue. Onset typically occurs two to 14 days after exposure. Dehydration is a serious risk, and hospitalization is not uncommon, though death is rare.
What Happens Next
Watch for three things in the coming days. First, whether the FDA names a new suspected source or broadens the investigation beyond Taylor Farms, given that the original lab result no longer supports the linkage. Second, whether state health departments — now carrying the surveillance burden after the CDC’s 2025 pullback — can keep pace with case counts that are already straining capacity in Michigan and Ohio. Third, whether additional restaurant chains disclose that they received recalled lettuce, which would expand the consumer exposure window.
The false positive also puts pressure on the FDA to explain its Cyclospora testing methodology publicly. With thousands sick and a recall still in motion, confidence in the lab process matters as much as the results themselves. Consumers holding recalled Marketside or Taylor Farms food service product should check use-by dates through Aug. 3 and discard anything in the affected window, regardless of the laboratory reversal.
— Aisha Mensah, health desk, AXO News