Protecting families from contaminated food and water
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Protecting families from contaminated food and water
Posted in Cyclospora,Cyclospora,Our Blog,Outbreaks & Recalls on July 21, 2026
A Cyclospora false positive has temporarily cleared Taylor Farms from the current multistate outbreak. However, the company maintains their recall as a preventative measure.
But what exactly does a false positive mean? Does it happen often? What does this mean for consumers?
But first, let’s take a look at the most recent information on this multistate Cyclospora outbreak!
If you are looking up information on a Cyclospora outbreak right now, it can be a bit confusing.
States are reporting numbers that appear inconsistent with national numbers. Heck, the U.S. Food and Drug Administration (FDA) has five different outbreaks listed on their active foodborne illness outbreak table dating back to early June. Being listed separately is an indication that both genetic data and food interviews tell outbreak investigators that these outbreak clusters are likely to be unrelated.
So, how many people are impacted?
According to the FDA, this outbreak linked to lettuce impacting five states has 1,644 confirmed cases with 94 hospitalizations. Indiana, Kentucky, Michigan, Ohio, and West Virginia have been impacted by cases with genetically similar Cyclospora germs.
This does not account for cases awaiting confirmatory testing, probable cases, and others not epidemiologically confirmed to be connected to this outbreak likely involving lettuce.
In fact, it is only a fraction of what Michigan Health and Human Services has reported. As of July 21, 2026, this includes 6,571 illnesses and 102 hospitalizations.
This outbreak has a strong connection to lettuce. Specifically, iceberg lettuce.
Michigan has so far received the most reports of Cyclospora illness across the country. They have been a huge resource for the FDA and CDC in this outbreak.
According to their patient interviews, a significant number of cases reported eating at Taco Bell. Ingredient level analysis indicated that 90% consumed iceberg lettuce.
Additionally, the same lettuce supplier services Taco Bells in all five states involved in the outbreak.
Taylor Farms de Mexico.
This led investigators to begin product sampling there. Initial reports said product samples were positive for the presence of Cyclospora. However, recent reports indicate this result is a “false positive.”
What exactly does that mean?
A false positive means that the results of the sample assay (a type of laboratory test) were inaccurately found to be positive.
False negative results are more common than false positive results because small sample size or inadequate DNA extraction may limit the amount of detectable sample used in the assay.
However, false positives can happen (like in a pregnancy test).
Sometimes due to something interfering with the test result, a contaminated assay, or misinterpreting results. The specific reason for the false positive was not indicated, so I will explain how each of those scenarios may have occurred.
I am assuming that a Polymerase Chain Reaction (PCR) DNA analysis was performed based on the statement indicated in the update:
“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.”
Typically, PCR is used to screen pathogens in these scenarios. As a molecular biologist, PCR happens to be an assay I am very familiar with.
In some cases, organisms share a good amount of DNA. If there is overlap in the specific genetic segments (target DNA) used in the assay to detect the organism, there could be a false positive. This is more likely to happen in research laboratories where they are building the assays from scratch.
It is unlikely that this occurred in this circumstance.
In some cases, an assay can become contaminated. Either contamination happens while the assay is being put together or the reagents used in the assay were contaminated.
A “positive control” and a “negative control” are used in every assay. The positive control ensures that the reagents work. Those assays should always amplify as expected. The negative control ensures that there is no contamination in the reagents. That assay should always be negative.
Most protocols require sample wells to be covered prior to adding positive control to the assay, so this is also an unlikely scenario.
While I have no specific evidence to say that the results were misinterpreted (aside from the FDA statement), this is the most likely reason.
Small sample sizes generate a smaller quantitative result on a PCR assay. These assays often run a specific number of cycles based on what is being detected and the amounts of reagents used in the assay. As the assay nears the end of the number of cycles in the assay or if it is run beyond the recommended number of cycles, sometimes “artifacts” form.
Those artifacts may appear as a small amplification (an indication of the presence of trace amounts of the target DNA).
A false positive may have been identified when subsequent testing proved negative or a culture did not grow for confirmatory testing.
So, what does this mean for consumers?
We aren’t exactly at square one. Iceberg lettuce is still the frontrunner for likely food source in this outbreak. But it has not yet been confirmed.
It is still a good idea to take precautionary measures for all potential food sources.
Foods like raspberries, lettuce, basil, and cilantro.
Choose frozen berries (or better yet, cook them). Avoid uncooked herbs. Wash lettuce well. Never consume recalled product.
Things like that.
Speaking of recalled product. Taylor Farms has decided to maintain their recall, “removing all iceberg lettuce sourced from central Mexico from the U.S. market.”
Which products are subject to recall?
Affected product was sold at Walmart stores in Alabama, Arkansas, Florida, Georgia, Indiana, Kansas, Kentucky, Louisiana, Missouri, Massachusetts, Oklahoma, Tennessee, Texas, Virginia, and West Virginia.
Recalled products sold at Walmart include:
Cyclospora is a parasite that can infect humans. In fact, humans are the only known host for this harmful microorganism.
If you recently experienced gastrointestinal symptoms, it is a good idea to compare what you are going through with common Cyclospora symptoms. You may be part of this Cyclospora outbreak or another cluster under investigation.
The most notable symptom involves watery diarrhea, with “frequent, sometimes explosive, bowel movements.” Most people with Cyclospora infections also report feeling very tired or more tired than usual.
Additional symptoms may include:
It is possible for someone who is infected with Cyclospora to experience no symptoms at all. This is more common in areas where Cyclospora is endemic. It is important to note that a non-symptomatic person can still shed Cyclospora.
If you believe you have been impacted by this Cyclospora outbreak linked to iceberg lettuce, it is a good idea to get advice from an experienced Cyclospora Lawyer. They can answer your questions, investigate your case, and help you get the compensation you need. Lost work, caring for a loved one, medical bills, and other burdens associated with foodborne illness add up. A Cyclospora lawyer can help you recover those losses.
The Lange Law Firm, PLLC has a Cyclospora Lawyer that can help!
You want experienced representation, skilled at handling cases just like yours. The Lange Law Firm, PLLC has successfully recovered millions of dollars in products liability and food poisoning cases, and they can help you too.
Call (833) 330-3663 or send an email for your free, no obligation consultation.
By: Heather Van Tassell (contributing writer, non-lawyer)