All the romaine lettuce in the U.S. is currentlyunsafe to eat, the Centers for Disease Control andPrevention has said, warning consumers that an E. coli outbreak is linked to the salad staple.
The warning comes after 32 people in 11 statesreported E. coli infections. The number of ill people isexpected to increase, says Laura Gieraltowski, teamlead of the CDC's foodborne outbreak responseteam.
Gieraltowski says the CDC took the somewhat extreme measure of warning people to avoidall romaine lettuce because the agency has not yet identified a common grower or supplierthat could be the source of the outbreak.
California, which grows the majority of romaine lettuce shipped around the country this timeof year, has reported the highest number of E. coli cases in the current outbreak, with 10 people infected so far. Investigators will likely look into those cases to determine where thelettuce came from and where it was sent.
"Where the cases are can often give us information on how the food was distributed," Gieraltowski says.
Romaine lettuce itself is not inherently more likely to cause E. coli outbreaks than similarproduce. But vegetable row crops, which include leafy greens like romaine, are a majorsource of E. coli, according to Gieraltowski.
Such crops are responsible for about 40% of E. coli outbreaks.