Eric and Ryan Jensen filed documents Tuesday notifying the court that they would plead guilty to unspecified charges under the agreements. Details typically aren't disclosed until the hearing where defendants formally change their pleas.
Ryan Jensen's lawyer, Richard Banta, declined comment Wednesday and Eric Jensen's lawyer didn't immediately return a call. A prosecutors' spokesman wasn't available to comment because of the government shutdown.
The brothers were charged last month with introducing adulterated food into interstate commerce. At the time, the Food and Drug Administration said the rare move was intended to send a message to food producers.
According to the FDA, conditions at Jensen Farms in southeast Colorado led to the 2011 outbreak. 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 equipment.
Officials said people in 28 states ate the contaminated fruit, and 147 required hospitalization.
Criminal charges are rare in food-borne illnesses, but the FDA under President Barack Obama has been more aggressive in pursuing farmers and food processors for alleged lapses.
In February, four former employees of a peanut company were charged in Georgia federal court with scheming to manufacture and ship tainted peanuts. A 2009 salmonella outbreak blamed on the peanuts killed nine people and sickened hundreds.
The four pleaded not guilty.
The Jensens each faced up to six years in prison and $1.5 million in fines had they been convicted of all of the original charges against them. Their lawyers have requested that they be allowed to change their pleas on Oct. 22 but the judge hasn't set a date yet.