North American health officials are urging consumers to throw out their romaine lettuce. 

On Tuesday, the Centers for Disease Control and Prevention issued a food safety alert about an E. coli outbreak that has been linked to the popular leafy green. The CDC reports 32 people—including 13 who have been hospitalized—were infected with E. coli O157:H7 across 11 states: California, Connecticut, Illinois, Massachusetts, Maryland, Michigan, New Hampshire, New Jersey, New York, Ohio, and Wisconsin. Canadian officials also confirmed an additional 18 people were infected by the same strain.

"Consumers who have any type of romaine lettuce in their home should not eat it and should throw it away, even if some of it was eaten and no one has gotten sick," the CDC alert read. "This advice includes all types or uses of romaine lettuce, such as whole heads of romaine, hearts of romaine, and bags and boxes of precut lettuce and salad mixes that contain romaine, including baby romaine, spring mix, and Caesar salad."

Retailers and restaurants have also been asked to stop selling and/or serving romaine lettuce.

The CDC states symptoms usually appear about three to four days after exposure; these symptoms include everything from severe stomach cramps and diarrhea to vomiting and fever. Though the severity of the infections vary from person to person, the agency reassured consumers that the most individuals recover within five to seven days. 

Officials have yet to identify a source of the contaminated lettuce, which is why they haven't issued a recall. Food and Drug Administration Commissioner Scott Gottlieb said the agency decided to issue the warning before families celebrated Thanksgiving. 

"It's still early in this investigation and work remains to pinpoint the source of contamination that contributed to this outbreak," Gottlieb said in a release. "We did feel some pressure to draw conclusions as quickly as we could."