His products have killed eight people and sickened 550 more, but Stew Parnell isn't giving any explanations. Hauled before the House Commerce Committee yesterday to testify under subpoena, the Peanut Corporation of America boss was offered a sample some of the peanut butter he shipped, which had tested positive for salmonella, but declined. He also skipped an earlier panel, which heard grieving relatives of victims of the tainted products. When asked about it all later, Parnell invoked his Fifth Amendment right to silence. The FDA says Parnell's company knowingly shipped products tainted with salmonella at least a dozen times. "You heard the last panel, did you not?" asked Rep. Bart Stupak (D-Mich.). "On advice of my counsel, I respectfully decline to answer your question based on the protection afforded me in the United States Constitution," Parnell answered.