The U.S. Food and Drug Administration (FDA) said on Sunday that laboratory experts re-reviewed sample results in the Taylor Farms Cyclospora investigation and concluded the finding should be considered a false positive.

The FDA issued an update on the cyclospora outbreak in the United States late Friday, confirming that a single supplier has been identified as the source.

Taylor Farms de Mexico lettuce sample tested positive for cyclospora, FDA said, as officials investigate a multistate outbreak of the parasite.

We still don’t know the source of the outbreak.

As of Sunday, the FDA said there are no confirmed positive sample results for Cyclospora.