Federal investigators have linked one of the largest documented outbreaks of foodborne illness in United States history to shredded iceberg lettuce, after tracing thousands of Cyclospora infections to a single Mexican processing plant supplying Taylor Farms de Mexico. The Food and Drug Administration and Centers for Disease Control and Prevention say the outbreak has now reached 11,458 confirmed illnesses across 20 states, with 495 hospitalizations and two deaths, making it the largest Cyclospora outbreak ever recorded in the country.
How the Trail Led to a Single Processor
FDA traceback investigators first identified a cluster of illnesses tied to Taco Bell locations in Indiana, Kentucky, Michigan, Ohio and West Virginia in mid-July, then traced the shredded iceberg lettuce those restaurants served to a single supplier: Taylor Farms de Mexico, a central Mexico-based processor. On July 17, the company voluntarily removed all iceberg lettuce sourced from central Mexico from the U.S. market and initiated a recall covering both foodservice and retail products. Taco Bell said the same day it had stopped using lettuce from that supplier.
The Case Count Behind “One of the Largest on Record”
According to research compiled by the consumer advocacy group U.S. PIRG Education Fund using CDC and FDA data, the lettuce-linked outbreak now ranks as the third-largest documented foodborne illness outbreak in American history, behind a 1994 ice cream Salmonella outbreak estimated at 224,000 illnesses and a 1985 milk Salmonella outbreak estimated at up to 197,000 illnesses. Both of those events predate PulseNet, the CDC’s genetic-fingerprinting system launched in 1996 that links bacterial illnesses across state lines, meaning few outbreaks investigated with modern tools have approached this scale. Illness onset dates in the current outbreak range from June 14 to August 15, and officials say the true number of infections is almost certainly higher than the confirmed count, since Cyclospora testing is not routine and some people recover without seeking care.
Genotyping Ties the Illnesses to a Single Source
To confirm that geographically scattered illnesses share a common origin, public health investigators performed Cyclospora genotyping on samples collected from sick people, a technique that groups genetically related parasites using specific molecular markers rather than the whole-genome sequencing used for bacterial outbreaks. The CDC said the genotyping results show the Cyclospora parasites behind these illnesses are genetically related, reinforcing the epidemiological and traceback evidence that pointed to Taylor Farms de Mexico’s iceberg lettuce as the shared source.
What Was Recalled, and Where It Went
The recall covered multiple lot codes and package types, including Marketside-brand iceberg salad and shredded lettuce sold at Walmart with best-by dates from July 18 through August 3. Confirmed foodservice distribution reached more than 30 states, from Alabama and Florida to Wisconsin and West Virginia, with possible further distribution to several additional states and Puerto Rico. The FDA says the best-by dates on all recalled lettuce have now passed and the product should no longer be available in stores or restaurants, though the agency’s onsite inspections and sampling at growers and the processing facility in Mexico remain ongoing.
Why Cyclospora Investigations Move Slowly
Unlike Salmonella or E. coli, Cyclospora infections can take as long as six weeks to confirm as part of a specific outbreak, which is why the case count climbed steadily for months after the initial recall rather than plateauing immediately. The reported total moved from 1,644 illnesses across five states in mid-July, to 6,358 across 15 states in early August, to 9,481 in mid-August, to 10,930 by August 20 and finally 11,458 across 20 states by August 27, with Georgia, Tennessee and Texas the last three states added to the list. Most of the illnesses linked to this outbreak began before the July 17 recall took effect, reflecting that lag between exposure and confirmation, and state health departments sometimes publish different local counts because they include probable cases that CDC and FDA do not. The CDC said in its most recent update that it is scaling back the frequency of its public reports as the number of newly linked cases declines, a sign the outbreak’s growth phase has largely passed even as the final tally continues to be finalized.
Recognizing Cyclospora and When to Seek Care
Most people infected with Cyclospora develop watery diarrhea with frequent bowel movements, along with loss of appetite, weight loss, cramping, bloating, gas, nausea and fatigue; some develop vomiting, body aches, headache or fever, while others have no symptoms at all. Left untreated, the infection can cause dehydration and complications lasting from a few days to a month or longer, and symptoms can relapse after appearing to resolve. The FDA advises anyone who ate shredded iceberg lettuce in the two weeks before symptoms began to contact a health care provider, particularly people who are immunocompromised, who the agency says can experience more severe and prolonged illness. Full case data and updates are available on the FDA’s outbreak investigation page and the CDC’s parallel case update.
This article was produced with the assistance of AI and reviewed by Morning Overview editors prior to publication.
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