Officials at the Food and Drug Administration and the Centers for Disease Control and Prevention, which have been investigating the outbreak of salmonella illness, said yesterday that Peanut Corporation of America found salmonella in internal tests a dozen times in 2007 and 2008 but sold the products anyway, sometimes after getting a negative finding from a different laboratory.

Companies are not required to disclose their internal tests to either the FDA or state regulators, so health officials did not know of the problem. [Link]