The Centers for Disease Control and Prevention advises U.S. consumers to not eat romaine lettuce, and retailers and restaurants to not serve or sell it.
CDC said Nov. 20 that the investigation is ongoing.
According to CDC, 32 people have been infected from E. coli O157:H7 in 11 states. Illnesses started in the Oct. 8-31 range. So far 13 people have been hospitalized.
The Public Health Agency of Canada reports 18 people infected with the same DNA fingerprint of E. coli in two Canadian provinces: Ontario and Quebec.
Epidemiologic evidence from the United States and Canada indicates that romaine lettuce is a likely source of the outbreak, CDC said.
CDC is advising that consumers do not eat any romaine lettuce because no common grower, supplier, distributor, or brand of romaine lettuce has been identified.
Produce industry groups released a joint statement the afternoon of Nov. 20 saying consumer protection is the No. 1 goal.