9 Calif. farms the focus in E. coli probe

Health authorities hunting the source of a nationwide E. coli outbreak are focusing on nine California farms after discovering what could be a crucial clue: an opened bag of spinach left in the refrigerator of someone sickened by the bacteria.

The bag of tainted Dole baby spinach is the "smoking gun" that has allowed investigators to zero in on three counties in California's greater Salinas Valley, said Dr. Mark Horton, the state public health officer. Authorities also were checking processing plants, Horton said.