Two former executives with the Peanut Corporation of America and a broker who worked with the company received prison sentences for their roles in the contamination of peanut products with salmonella that led to the deaths of nine and sickened more than 700.

Stewart Parnell, the former owner and president of the Lynchburg, Va.-based company, was sentenced to 28 years in prison. Mr. Parnell is 61.

Michael Parnell, 56, the brother of Stewart Parnell who was employed as a broker for P.P. Sales and worked on behalf of PCA, was sentenced to 20 years in prison. Mary Wilkerson, who was the quality assurance manager at the PCA plant in Blakely, Ga., was sentenced to 5 years in prison.

The Parnell brothers were convicted by a federal jury on Sept. 19, 2014, of multiple counts of conspiracy, mail and wire fraud and the sale of misbranded food. Stewart Parnell also was convicted of the introduction of adulterated food into interstate commerce. Stewart Parnell and Mary Wilkerson also were convicted of obstruction of justice.

Stewart Parnell was found guilty of all but one of the 68 felony counts with which he was charged on Feb. 15, 2013.

“Americans should be able to trust that the food we buy for ourselves and our families is safe,” said Stuart F. Delery, acting associate attorney general. “The sentences handed down today to officials associated with the Peanut Corporation of America demonstrate the consequences for those whose criminal actions threaten that trust by introducing contaminated food into the marketplace. Our prosecution is just one more example of the forceful actions that the Department of Justice, with its agency partners, takes against any individual or company who compromises the safety of America’s food supply for financial gain.”