As a outcome, the Public Health Agency of Canada is asking Canadians to avoid consuming, selling or serving romaine lettuce from the region. "Very frustrating all around", said Trevor Suslow of the Produce Marketing Association.
A total of 40 people in 16 states have been infected from the contaminated lettuce, the CDC said.
First reports of the illness came to the CDC on September 24.
Laboratory evidence and interviews with the sickened consumers indicate that romaine lettuce from the Salinas region may be contaminated with this strain.
It's not clear exactly why romaine keeps popping up in outbreaks, but food safety experts note the popularity of romaine lettuce and the difficulty of eliminating risk for produce grown in open fields and eaten raw. There is no recommendation for consumers to avoid using romaine harvested from these other sources. Symptoms of infection include vomiting, painful cramps and diarrhea that is often bloody. If there is fever, it is usually not very high (less than 101 degrees Fahrenheit/less than 38.5 degrees Celsius).
"Most people recover within five to seven days", the Maryland Department of Health wrote earlier this week. Vigorous rehydration and other supportive care are the usual treatment; antibiotic treatment is generally not recommended. Wash and sanitize drawers or shelves in refrigerators where romaine lettuce was stored. And the same advice applies to mixed salads containing romaine when the growing area isn't known. If it did, or they do not know, do not eat it. These include whole heads, hearts, pre-cut packaged lettuce and salad mixes, including baby romaine, spring mix and Caesar salad, the agency said.
Romaine has been tied to repeated food poisoning outbreaks, including the one right before Thanksgiving a year ago.
The CDC told consumers to throw away any romaine lettuce they may already have purchased.
"We're concerned this romaine could be in other products", said Laura Gieraltowski, lead investigator of the outbreak at the U.S. Centers for Disease Control and Prevention. More information will be forthcoming as the investigation proceeds. A second outbreak that sickened more than 50 people in multiple states was linked to romaine lettuce from California's Central Coast. Restaurants should not serve it, stores should not sell it, and people should not buy it, if it was harvested from Salinas, a growing area in Northern California.