Romaine lettuce-linked E. coli outbreak expands

The search for the source of the outbreak is ongoing. The CDC and the Food and Drug Administration say the Yuma, Arizona, growing region is the source, but no farm has been identified. The Yuma area grows most of the lettuce harvested in the United States during the winter months, but officials say lettuce now in stores or at restaurants is probably from California's Central Valley or Salinas Valley and has not been implicated in the outbreak.