Taco Bell is removing lettuce from menus in some US states after health investigations linked shredded iceberg lettuce to an outbreak of cyclosporiasis, a parasitic infection that can cause severe watery diarrhoea. The precaution matters because the outbreak has affected large numbers of people and highlights concerns about tracing contaminated food through supply chains.

The CDC reported 1,645 infections among people exposed to Taco Bell in Indiana, Kentucky, Michigan, Ohio and West Virginia, with 94 hospitalisations and no reported deaths. The FDA advised against eating Taco Bell items containing shredded iceberg lettuce from Mexico in those states; supplier Taylor Farms said it was withdrawing central Mexican iceberg lettuce from the US market after an independent farm was identified as a potential source.