WASHINGTON  The Agriculture Department on Thursday banned the company implicated in the nationwide contamination of peanut products from doing business with the federal government. At least eight people have died and hundreds have been sickened after eating tainted products.

The order, which affects the Peanut Corporation of America and a subsidiary, will remain in force for one year. Agriculture Secretary Tom Vilsack also stripped the company’s chief executive of his seat on a board that advises the government on peanut quality standards.

David Shipman, an acting administrator at the Agriculture Department, said, “The actions of P.C.A. indicate that the company lacks business integrity and business honesty, which seriously and directly hinders its ability to do business with the federal government.”

The department’s actions came on a day when senators heard testimony from health experts and a Food and Drug Administration official, who acknowledged that gaps in the food safety system had contributed to delays in catching the outbreak of salmonella in peanut butter and other products that spread to 43 states. The problem has been traced to a peanut processing facility in Blakely, Ga.