The Food and Drug Administration has reversed its earlier determination in a widespread Cyclospora outbreak that has sickened more than 1,600 Americans with severe gastrointestinal illness.
Laboratory experts re-examined a sample of shredded iceberg lettuce from a Mexican supplier that had previously tested positive for the parasite. The agency now concludes the result was a false positive.
The FDA stated that due to the complexity of detecting Cyclospora, a review of the sample found no true amplification of the organism. The agency has removed the earlier finding from its public update and continues to analyze product samples with state partners.
The source of the outbreak remains unidentified. No confirmed positive product test for Cyclospora has been reported by the agency at this time.
The reversal follows days of disruption in which a supplier issued a voluntary recall of iceberg lettuce from central Mexico shipped to 27 states. The action came after federal investigators linked illnesses to shredded lettuce served at restaurant locations in five states.
The supplier said it was notified of the false positive after initially acting on preliminary health official guidance. The company emphasized that only iceberg lettuce from central Mexico was recalled and all other products remain unaffected.
Symptoms of Cyclospora infection include prolonged watery diarrhea, stomach cramps, bloating, nausea, fatigue, and sometimes fever. The illness can be especially severe for immunocompromised individuals.
Multiple retailers and distributors responded to the outbreak by pulling lettuce from supply chains. Restaurant operators removed iceberg lettuce nationally, while grocery and foodservice distributors halted related product distribution.
