Taylor Farms, a global producer of salads and fresh foods headquartered in California, says no single positive product test result was identified for cyclospora.

“To be clear, at this moment, FDA has not identified a single positive product test result for cyclospora,” said the company in a statement on Monday.

The clarification came after the FDA announced a positive test for cyclosporiasis in a Taylor Farms product that was outside the scope of the company’s ongoing voluntary recall.

“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 a statement.

The agency, however, noted that the false positive test was of a product that was not included in the recall and does not change the “very strong” epidemiological evidence connecting the company to the cyclosporiasis outbreak.

Last week, federal officials announced that the cyclosporiasis outbreak was linked to iceberg lettuce served at Taco Bell locations in five states and later confirmed a Taylor Farms facility in central Mexico supplied the lettuce.

The U.S. Centres for Disease Control and Prevention (CDC), in a safety alert, urged the public not to eat shredded iceberg lettuce from Taco Bell restaurants located in Indiana, Kentucky, Michigan, Ohio and West Virginia.

The agency said its officers, alongside other public health officials, had commenced an investigation into the multistate outbreak of cyclospora infections linked to lettuce served to consumers at the restaurants in the five affected states.

However, Taylor Farms insisted none of its branded salads or kits was associated with the outbreak.

The company added that the recall was limited to iceberg lettuce grown and processed in central Mexico and that “all other Taylor Farms products, including all Taylor Farms brand products available for purchase, are not involved in the recall.”