SILVER SPRING, Md. — The FDA said Sunday that, despite concerns that lettuce supplied by fruit and vegetable producer Taylor Fresh Foods was linked to Cyclospora infections, subsequent testing showed that none of the producer's lettuce tested positive for the parasite known for causing weeks of diarrhea. 

"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 FDA said in its update. 

Last week, Taylor Fresh Foods voluntarily removed all iceberg lettuce sourced from central Mexico from the U.S. market amid the ongoing cyclosporiasis outbreak across the country that has sickened more than 1,600 people.

As of Friday, the CDC said the multistate outbreak remains under investigation and is now linked to shredded iceberg lettuce that was served at some Taco Bell locations in Indiana, Kentucky, Michigan, Ohio and West Virginia.