Nov. 29 (UPI) -- The U.S. Food and Drug Administration said a multi-state E. coli outbreak in romaine lettuce has been narrowed to six California counties.
The FDA said in an update Wednesday it identified the counties that grew the contaminated lettuces -- Monterey, San Benito, San Luis Obispo, Santa Barbara, Santa Cruz and Ventura.
The agency has been investigating the outbreak with the Centers for Disease Control and Prevention and various health organizations.
"Additional counties may be added as the FDA traceback develops," the agency said. "Romaine harvested from locations outside of the California regions identified ... does not appear to be related to the current outbreak."
Lettuce from the Yuma, Ariz., region, the California desert near Imperial and Riverside counties, Florida and Mexico have all been cleared and safe to eat.
The FDA said there are 43 cases connected with the outbreak -- in California, New Jersey, Michigan and New York. Sixteen people have been hospitalized.
Last week, the FDA warned Americans not to eat any romaine on the market because of the illnesses.
E. coli (Escherichia coli) infections begin a few days after it's ingested. Symptoms include diarrhea, fever, abdominal cramps, nausea and vomiting. Most who are infected improve within a few days, but health officials said this particular strain of E. coli can be more severe.