Ninety-three percent of those who fell ill reported eating romaine lettuce prior to the sickness — many of which consumed salad at a local restaurant. Romaine lettuce was the only ingredient involved in every salad reportedly consumed. According to reporting by Patch.com, authorities reportedly considered a possible link between Panera Bread and a cluster of E. coli cases. It is still unknown whether the cases are directly related.
“Information collected to date indicates that chopped romaine lettuce from the Yuma, Arizona, growing region could be contaminated with E. coli O157:H7 and could make people sick,” the CDC website warns. “At this time, no common grower, supplier, distributor, or brand has been identified.”
The CDC advises consumers who have recently purchased romaine lettuce, including as part of salads and salad mixes, to throw it away, even if no one in your home has gotten sick. They also instruct that restaurants should not sell or serve romaine lettuce that has been sourced from the Yuma, Arizona, region. As of now, their investigation is ongoing.
To assess your area’s risk, see the full map of case counts from the CDC. If you’ve eaten a Caesar salad or other romaine-filled dish lately, be on the lookout for symptoms. These include diarrhea, severe stomach cramps, and vomiting. It’s decidedly unpleasant, and hard to miss.

We suppose it’s not too much of a shock that romaine was the source of the sickness — not only have similar romaine-related outbreaks happened before, but leafy greens are one of the common foods most likely to cause food poisoning.