A sample of shredded iceberg lettuce from Taylor Farms de Mexico has tested positive for Cyclospora, federal health officials said, as the company expanded a multistate recall tied to a growing multistate outbreak.

The U.S. Food and Drug Administration said the contaminated sample was collected through targeted import surveillance and was not part of Taylor Farms' current recall. The agency said the positive lot has been detained and the California-based produce company is working to determine whether any of the implicated lettuce remains in commerce or in consumers' homes.

The positive test result comes after Taylor Farms announced it was voluntarily recalling iceberg lettuce sourced from central Mexico, while removing all such lettuce from the U.S. market, because of potential Cyclospora contamination.

"We are actively removing the implicated products," Taylor Farms said in its recall notice. "The company has stopped receiving product from the implicated lot, suspended distribution of the iceberg lettuce from Central Mexico, notified our customers, and we are continuing to work with the FDA, CDC, and state authorities."

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The recall covers 12-ounce and 24-ounce bags of Marketside iceberg salad, as well as 8-ounce and 16-ounce bags of Marketside shredded iceberg lettuce distributed between June 29 and July 16 with "best if used by" dates ranging from July 18 through Aug. 3, according to the FDA. The recall also includes numerous products distributed to foodservice customers.

The affected lettuce was distributed in 27 states. The recall follows the FDA's announcement Thursday that Taco Bell would stop using lettuce from a supplier linked to the multistate cyclosporiasis outbreak, which has sickened 1,644 people and hospitalized 94 across five states. No deaths have been reported.

Taco Bell said it voluntarily removed potentially affected lettuce from the supplier in select states where illnesses have been reported.

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Taylor Farms had previously said its branded salad products were not associated with the outbreak.

In a statement posted to Instagram on Friday, the company reiterated that none of its branded salad kits are implicated and said it voluntarily removed iceberg lettuce sourced through its Taylor Farms de Mexico operation after receiving information from the FDA.

The FDA said its trace-back investigation Taylor Farms de Mexico as the supplier of shredded iceberg lettuce that was used at Taco Bell restaurants where infected customers reported eating before becoming ill. The agency said not every Taco Bell restaurant in the five states received lettuce from the supplier.

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The agency is investigating illnesses in Indiana, Kentucky, Michigan, Ohio and West Virginia, and has advised consumers in those states not to eat shredded iceberg lettuce from Mexico served at Taco Bell restaurants.

According to the FDA, Cyclospora is a microscopic parasite that can cause severe diarrhea, nausea, stomach cramps, fatigue and other gastrointestinal symptoms.

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The agency urged anyone who purchased the recalled lettuce to throw it away immediately or return it to the place of purchase for a refund.

FOX Business' Brittany Miller contributed to this report.