An irrigation reservoir was found to be contaminated. An outbreak of E. coli infections linked to romaine lettuce has been traced to at least one California farm, but it’s probably not the source of all the sicknesses, federal health officials said Thursday. So far, 59 people have been reported sick across 15 states in the outbreak, the Centers for Disease Control and Prevention said. The CDC said 23 have been sick enough to be hospitalized, although no one has died. Canadian health officials have reported 27 cases linked to the same outbreak. Investigators found the implicated strain of E. coli...