ALBANY, Ga. — More than five years after hundreds of Americans got sick from eating salmonella-tainted peanut butter, the top executive at the Georgia plant where it was made was convicted Friday and faces prison time in a rare food-poisoning trial that advocates said sends a stern warning to others who may be tempted to place profits over safety. Former Peanut Corporation of America owner Stewart Parnell, 60, could face more than three decades in prison after being found guilty of conspiracy, obstruction of justice, wire fraud and other crimes related to the outbreak in 2008 and 2009 that was linked to nine deaths and prompted one of the largest food recalls in U.S. history. His brother, Michael Parnell, and a second co-defendant could face 20 years in prison or more.