The U.S. Food and Drug Administration announced that a previous test identifying the Cyclospora parasite in shredded lettuce was a false positive [1].
This development leaves federal investigators without a confirmed source for a widespread cyclosporiasis outbreak that has affected consumers across 34 U.S. states [4]. Without a verified contaminated product, health officials cannot pinpoint how the parasite is spreading or how to stop further infections.
The FDA said that as of July 19, 2026, there are no confirmed positive sample results for product testing for cyclospora [1]. The initial test had identified the parasite in shredded lettuce sourced from central Mexico [1].
A spokesperson for Taylor Farms said the FDA had not identified any positive product test results for cyclospora [2]. The company's statement follows the agency's reclassification of the earlier laboratory result as erroneous [3].
Despite the lack of a positive product sample, the outbreak continues to impact public health. Investigators said they have no proof as to what is causing the cyclosporiasis outbreak that has sickened an estimated 7,000 people [3].
The discrepancy between the lack of positive tests and the high number of illnesses creates a challenge for regulators. While some reporting suggests the FDA still considers iceberg lettuce a likely culprit, the agency has not produced a confirmed positive sample to support that conclusion [2].
“As of July 19, 2026, there are no confirmed positive sample results for product testing for cyclospora.”
The reclassification of the test result as a false positive creates a critical gap in the public health response. Because the FDA cannot link the illness to a specific product or farm, they cannot issue targeted recalls or implement precise preventative measures at the source. This leaves 7,000 estimated victims without a clear cause and allows potentially contaminated produce to remain in the supply chain.
