"Stewart Parnell absolutely knew that they were shipping salmonella-tainted peanut butter. They knew it, and they covered it up," says Bill Marler, a food safety lawyer who represented some of the victims.
Before and during the outbreak, company executives assured customers that their products were free of salmonella when no tests had been carried out.
And when tests did turn up salmonella, company executives sometimes just retested that batch, and when it came up clean, they sold it.
In one memorable e-mail exchange, when Parnell was told that a shipment was delayed because results of salmonella tests weren't yet available, he wrote back, "Just ship it."
Last year, Parnell and two other people involved PCA's peanut business were convicted of criminal charges that included fraud, obstruction of justice, and selling adulterated food.
These were almost unprecedented charges in the food industry, and Marler says that executives in other companies are paying close attention. "The arrest of Stewart Parnell, his conviction on these felony counts, and his sentence have put a very big chill in the boardrooms of corporate America," he says.
The Peanut Corporation of America is no longer in business.
At the sentencing hearing for Parnell and his colleagues, relatives of some of the victims confronted Parnell with stories of their suffering. Parnell, for his part, asked for forgiveness and mercy, and said that he never intended to harm anyone. His daughter said that he sometimes brought his company's peanut butter home for his family to eat.
Along with Parnell's 28-year sentence, his brother Michael Parnell was sentenced to 20 years in prison, and another former executive was sentenced to five years.
All of these sentences are the harshest ever imposed in connection with an outbreak of foodborne illness.
In some other recent cases, companies sold contaminated eggs and cantaloupes that also were linked to multiple deaths. Executives in those companies were sentenced to probation and a few months in prison.
Stewart Parnell's lawyers have indicated that they will file an appeal.
Copyright 2015 NPR.