A federal magistrate in also ordered brothers Eric and Ryan Jensen to each pay $150,000 in restitution and perform 100 hours of community service. Each read a statement in which they apologized but didn't show any emotion during the hearing.
They pleaded guilty last year to misdemeanour counts of introducing adulterated food into interstate commerce and faced up to up to six years in prison and $1.5 million in fines.
The outbreak caused 33 deaths and sickened 147 people in 28 states. Relatives of seven of those who died testified during the hearing, with some asking for probation but others asking for prison time for the brothers.
Patricia Hauser, who lost her husband, asked Judge Magistrate Michael E. Hegarty to sentence both brothers to prison and a fine.
She described her husband's slow and agonizing death and recalled a time when he nearly choked to death on his own vomit while hospitalized.
"The look of terror on his face still gives me nightmares," she said.
Paul Schwarz, said his father, also named Paul — a World War II veteran with two Purple Hearts— died at the age of 92 from listeria.
"I never would have guessed that someone everyone regarded as a real American hero would die from something he ate," said Schwarz, who didn't make a recommendation on the Jensens' punishment.
Eric Jensen sat facing the lectern where the relatives testified and he watched all the victims speak. Ryan Jensen was seated beside the lectern and slightly in front and looked straight ahead. Both appeared to be listening attentively.
Hegarty made a point of saying he was not sentencing either brother to prison or to pay a fine so that the brothers could continue working to support their own families and pay restitution.
The U.S. Food and Drug Administration has said the rare move to charge the Jensens was intended to send a message to food producers.
Federal investigators said the melons likely were contaminated in the farm's packing house because of dirty water on the floor and old, hard-to-clean processing equipment. The Jensens said their operation was given a "superior" rating just a month before the outbreak their independent auditors, whom they are now suing. The Jensens have said that any money they get from the civil suit would go to the victims of the outbreak.
Attorney William Marler, who represented the families of 24 people who died in the outbreak, also has said probation would be adequate. He said farmers, retailers and the federal government learned valuable lessons and there are now new regulations in place that will reduce the likelihood of a repeat tragedy.
The Jensens had argued themselves that probation would allow them to try to raise more money for restitution. The request was backed by prosecutors, who gave the brothers credit for meeting with the families of many of the victims and assisting in the outbreak investigation.
Attorneys say the two men have already filed bankruptcy that provided nearly $4 million to victims and their families. Marler and other attorneys are suing retailers and auditors involved in the case after a bankruptcy judge estimated damages at $50 million.