(TNND) — The U.S. Food and Drug Administration (FDA) is reversing its earlier finding that detected cyclospora in a sample of lettuce from Taylor Farms, saying the result was a false positive as investigators continue probing a multistate outbreak that has sickened more than 1,600 people.
“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 and should be considered a false positive,” the agency said in a statement.
As of Sunday, the FDA said there were no confirmed positive food sample results for Cyclospora and that the outbreak investigation remains ongoing.
Taylor Farms said the FDA apologized to the company after determining the initial laboratory finding was incorrect.
“Today, we were informed that FDA made a mistake, and this was a false positive,” the company said in a statement. “To be clear, at this moment, FDA has not identified a single positive product test result for Cyclospora.”
Taylor Farms said it voluntarily recalled iceberg lettuce from central Mexico “out of an abundance of caution” after receiving the FDA’s initial findings. The recalled products were limited to iceberg lettuce grown and processed in Mexico.
Last week, health officials said the outbreak had been linked to shredded lettuce served at Taco Bell restaurants in five states.
According to the Centers for Disease Control and Prevention (CDC), illnesses have been associated with shredded lettuce served at Taco Bell locations in Kentucky, Indiana, Michigan, Ohio and West Virginia.
As of Saturday, the CDC reported 1,644 cases and 94 hospitalizations but no deaths.
Cyclosporiasis is an intestinal illness caused by the microscopic parasite Cyclospora cayetanensis. People become infected after eating food or drinking water contaminated with the parasite.
Unlike many other gastrointestinal illnesses, Cyclospora is not typically spread from person to person because the parasite must spend days to weeks in the environment before it becomes infectious.
Symptoms usually develop about a week after infection and include frequent watery or “explosive” diarrhea, loss of appetite, weight loss, stomach cramps, bloating, nausea, vomiting, fatigue and a low-grade fever.