Test that found source of US explosive diarrhoea outbreak was false positive, health officials say

What the report says

Nile Post, carrying a BBC report, said US health officials have withdrawn an initial finding that appeared to identify a source of a Cyclospora outbreak linked to iceberg lettuce. The Food and Drug Administration had reported on Saturday that a sample from Taylor Farms, a supplier to Taco Bell, tested positive for the parasite. On Sunday, the agency said laboratory experts re-examined the result and determined it was a false positive.

The reversal means investigators have not confirmed the exact source of the outbreak. According to the report, no deaths have been recorded, but at least 94 people have been hospitalized. The FDA said it is still working with Taylor Farms to ensure products associated with the outbreak are no longer on the market. The sample in question was collected during targeted import surveillance as part of the investigation.

Taylor Farms had already moved to remove iceberg lettuce sourced from central Mexico from the US market and listed affected products. The FDA said the positive sample initially reported came from a product outside the company’s current Friday removal action. The report noted that recalls are generally broader than voluntary removals because they require customer notification and recovery of products from commerce.

The infections were first detected on 13 May, the FDA said. The CDC has advised consumers not to eat shredded iceberg lettuce served at Taco Bell restaurants in Indiana, Kentucky, Michigan, Ohio and West Virginia. Taco Bell said it had completed removal of affected Taylor Farms lettuce, while Taylor Farms said it had halted receipt and distribution of the implicated lettuce and was cooperating with federal and state authorities.