Testing of opened peanut butter jars obtained from people sickened by salmonella has confirmed the presence of the dangerous germ, the Centers for Disease Control and Prevention said Thursday.

ConAgra Foods Inc. last week recalled all Peter Pan and Great Value peanut butter made at its Sylvester, Ga., plant after federal health officials linked the product to a salmonella outbreak that has sickened at least 329 people from 41 states since August. No deaths have been confirmed, although a Pennsylvania family filed a lawsuit Wednesday claiming a relative died from eating tainted peanut butter.

Federal officials linked the peanut butter to the outbreak by surveying people who became ill, but until now there had been no lab results to confirm the connection.

State health departments asked sickened people to bring in opened jars of peanut butter for testing, and jars in New York, Oklahoma and Iowa tested positive, said Dave Daigle, a CDC spokesman in Atlanta.