FDA Retracts Positive Lettuce Test Amid Recall

The Food and Drug Administration (FDA) on Sunday retracted a previously announced positive laboratory test that had tentatively linked Taylor Farms lettuce to the ongoing cyclospora outbreak. This withdrawal does not alter the current scope of the recall but may prevent its expansion. The FDA had reported on Saturday a positive test for cyclospora in Taylor Farms lettuce that was not part of the active recall, suggesting a potential broadening of the recall.

By Sunday evening, the agency revised its statement, explaining that upon re-examination by laboratory experts, the initial finding was determined to be a false positive. The FDA stated, "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." Taylor Farms subsequently commented that the "FDA has not identified a single positive product test result for cyclospora."

Despite the retracted lab result, health officials continue to investigate Taylor Farms produce as a potential source of the outbreak. This investigation is complicated by the short shelf-life of lettuce and the specific challenges associated with testing for cyclospora. Cyclosporiasis, a gastrointestinal illness caused by the parasite cyclospora, has affected individuals in 34 U.S. states, according to the Centers for Disease Control and Prevention (CDC). As of July 17, Michigan reported over 5,000 illnesses, the highest case count among states, with state-level data typically lagging behind national figures. Symptoms of the illness, including severe diarrhea and nausea, can manifest up to two weeks after ingestion, making source tracing difficult for federal health authorities. The CDC employs epidemiologic data, traceback investigations, and food and environmental testing to investigate foodborne outbreaks.