The tally of people sickened by the parasite is now 11,458.
"Country of Origin Labeling" -- or COOL -- is a federal requirement for many fresh fruits and vegetables, some meats, seafood, and certain nuts.
There may be other potential sources behind the outbreak.
The outbreak has sickened at least 1,600 people in five states.
The largest cluster is linked to iceberg lettuce from Taco Bell in five states.