This is the biggest Shiga-toxin producing E. coli outbreak since a 2006 outbreak linked to spinach grown in the Salinas Valley in California, Wise said.
It has now sickened 28 more people and affected four more states, confirms the Centers for Disease Control and Prevention.
Thus far, the current romaine lettuce outbreak has affected 29 states. One death from California has been reported. Seventeen have developed a unsafe form of kidney failure, and one person in California has died.
Scientists have identified a link to romaine lettuce grown in the Yuma, Arizona region.
If any symptoms of E. coli infection surface, the U.S. Department of Health and Human Services recommends drinking lots of fluids and getting rest as well as contacting a health care provider.
Illnesses began on dates ranging from March 13 to April 25, according to the CDC. "This percentage is significantly higher than results from a survey of healthy people in which 46% reported eating romaine lettuce in the week before they were interviewed". By the end of May, it's possible that more cases will be recorded.
People usually get sick from this strand of E. coli 2-8 days after ingesting the germ. Symptoms include vomiting, diarrhea and stomach cramps.
Most people recover within the first week, according to the CDC, but some infections can be severe.
The CDC cautions against the use of antibiotics when dealing with this strain of E. coli because studies have connected antibiotic use with an increased risk for hemolytic uremic syndrome in both children and adults.
Behm says in extreme cases E.coli can even cause kidney damage and death.
The agency says if it is determined that contaminated romaine lettuce is in the Canadian market, the Canadian Food Inspection Agency will recall the product as required.
The CDC continues to urge consumers to avoid eating or buying any kind of romaine lettuce from the Yuma region.