If you can not be certain a salad is free of romaine lettuce, do not eat it.
This nasty outbreak has infected 172 people across 32 states, according to the CDC.
The latest update released by the Centers for Disease Control on Wednesday updates advice to consumers.
Newly reported cases are people who became sick two to three weeks ago, still within the window when contaminated romaine was available for sale.
According to the U.S. Food and Drug Administration's information about the outbreak, there have been 64 hospitalizations and one death during the months of March and April. It is unlikely that any romaine lettuce from the Yuma growing region is still available in people's homes, stores, or restaurants due to its 21-day shelf life.
The CDC said 20 people had developed a severe outcome of E. coli infection called hemolytic uremic syndrome.
Officials with the Wisconsin Department of Health Services said Wednesday, May 16 there is one new case of E. coli linked to romaine lettuce in the state of Wisconsin. The strain of E. coli, known as O157:H7, produces a Shiga toxin that can affect people seriously, causing diarrhea and vomiting and in severe cases kidney failure. As of May 15, the CDC was reporting three people were ill from the outbreak in Colorado. Product labels often do not identify growing regions; so, throw out any romaine lettuce if you're uncertain about where it was grown. A previous warning was limited to chopped forms of romaine, including salads and salad mixes.
Now three more states have reported ill people: Iowa, Nebraska, and OR, the CDC said.
While most strains of the bacteria E. coli are harmless, others can cause serious illness.