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

The FDA says an initial positive test for cyclospora on a Taylor Farms iceberg lettuce sample was a false positive after re‑review.
The exact source remains unknown — thousands have been sickened and at least 94 hospitalised; CDC warns against shredded iceberg lettuce at Taco Bell in IN, KY, MI, OH and WV.
Taylor Farms has voluntarily pulled iceberg lettuce from its central Mexico supply, Taco Bell removed the lettuce from menus, and related products in multiple states (including some Walmart Marketside items) were affected.