The US Centers for Disease Control and Prevention said the total number of those infected has climbed to 24. Of 13 sick people interviewed, all reported eating a type of vegetable with leafy leaves, some ate romaine lettuce, but health officials said that "no common supplier, distributor or retailer of green leafy vegetables has been identified".
The CDC said it is unable to recommend whether Americans should avoid lettuce, as it has not concluded their investigation.
Pressure had been mounting on the CDC and the Food and Drug Administration (FDA) to provide more information to the public about this outbreak.
The Center for Disease Control, several states, and the U.S. Food and Drug Administration are investigating at least 17 people sickened in 13 states: California (3), CT (2), IL (1), in (1), MI (1), Nebraska (1), New Hampshire (2), NY (1), OH (1), Pennsylvania (1), Virginia (1), Vermont (1) and Washington (1). "CDC confirmed the outbreak on December 28-almost a month and a half after the first infection", said DeLauro.
Leafy greens have a short shelf life, and it's not likely contaminated greens tied to this outbreak are still available for sale, the CDC said in a statement.
"Without knowing exactly what caused this outbreak, we risk seeing a new batch of tainted product come onto the market", he said.
In response to the statements made January 10 by USA and Canadian health officials, a coalition of produce industry associations from both countries issued guidance related to the recent outbreak.
Maryland and New Jersey now join California, Connecticut, Illinois, Indiana, Michigan, Nebraska, New Hampshire, New York, Ohio, Pennsylvania, Vermont, Virginia and Washington, which all previously reported cases of illness. Five of them have been hospitalized, two have developed hemolytic uremic syndrome (HUS), and one death has occurred in California.
Consumer Reports issued a warning late last week about eating romaine.
Consumer Reports say you should also stay away from romaine lettuce served in a cafeteria or restaurant.
Which is why, although Canadian officials urged consumers to avoid romaine lettuce, US health authorities have not yet identified which type of "leafy greens" had led to the spread of the illness. One person has also died in Canada. The infections are all due to E. coli O157:H7 strain of the bacteria that produces the Shiga toxin.
Most people develop diarrhea (often bloody) and stomach cramps.