The U.S. Food and Drug Administration has officially concluded its investigation into the cyclosporosis outbreak that swept across the United States this summer, identifying the potential source of the contamination in Mexican lettuce production facilities.
Contamination Found in Wastewater and Drainage Samples
In a bulletin published Friday, October 2, the FDA announced that environmental samples collected from a lettuce producer and a processing facility in Mexico tested positive for the parasite Cyclospora cayetanensis. The outbreak, colloquially dubbed “explosive diarrhea” for its severe gastrointestinal symptoms, affected at least 12,883 people, caused 570 hospitalizations, and resulted in two deaths before officially ending on September 11.
Investigators had previously determined that a portion of the infections originated from a Mexican lettuce supplier whose products were used by Taco Bell restaurants across nine U.S. states. The FDA collected samples from several lettuce producers and from the Taylor Farms de Mexico processing plant. Two samples returned positive results:
- One sample was taken from a wastewater reservoir at the outlet of the Taylor Farms de Mexico facility
- The second was collected from a drainage ditch at an identified iceberg lettuce producer
Chain of Contamination Remains Unclear
“While there is currently insufficient evidence to conclusively determine how contamination occurred during this outbreak, the positive samples demonstrate that Cyclospora was present in the environment where the lettuce was grown and processed,” the FDA stated, justifying the closure of its investigation.
The agency considers the threat to be over, noting that “the expiration dates of the recalled lettuces have passed and the products should no longer be available in stores or restaurants.”
Taylor Farms Responds to Findings
In a statement cited by ABC News, Taylor Fresh Foods said that “the independent producer where a positive sample was detected is no longer part of our supplier network.” The company added that its facility remains closed while enhanced safety protocols are implemented.
“As the FDA noted in its report, there is currently insufficient evidence to conclusively determine how the contamination occurred or what link exists between these sample results and the ongoing genotyping of clinical samples,” the company added.
Background on Cyclosporosis
Cyclosporosis is caused by the microscopic parasite Cyclospora cayetanensis, which is transmitted through contaminated food or water. Symptoms typically include watery diarrhea, loss of appetite, weight loss, stomach cramps, bloating, gas, nausea, and fatigue. The illness can last for weeks or months if untreated.
The outbreak represents one of the largest foodborne illness incidents in recent U.S. history, prompting widespread product recalls and heightened scrutiny of imported produce safety protocols.
