CNN Business has produced a headline so pure, so direct, so violently inevitable, that no rewrite desk should be allowed within 500 feet of it: "Taco Bell has a diarrhea problem."The actual story is grim and gross: CNN reports that shredded iceberg lettuce sold at some Midwestern Taco Bell locations has been linked to a cyclospora outbreak involving more than 1,600 cases and nearly 100 hospitalizations.