The owners of a US cantaloupe farm linked to a 2011 listeria outbreak that killed 33 people have been arrested, federal investigators said today (26 September).

Eric and Ryan Jensen were charged with introducing adulterated food into interstate commerce.

The outbreak was the deadliest foodborne illness outbreak in the US in over 25 years.

In January 2012, a US federal investigation into the outbreak found Colorado-based Jensen Farms had ignored government safety guidelines.

Officials from the Food and Drug Administration who visited the facility found 13 samples of listeria monocytogenes obtained from processing equipment and cantaloupes. They found dirty water pooling around the food processing equipment, inappropriate food processing equipment which was difficult to clean and no antimicrobial solution in the water used to wash the cantaloupes.

A statement issued today by the US Attorney’s Office for the District of Colorado claimed the brothers changed the system they used to clean the cantaloupes – but did not use a chlorine spray needed to wash the produce.

Eric, 37, Ryan, 33, “were aware that their cantaloupes could be contaminated with harmful bacteria if not sufficiently washed”, the statement read.

As well as the 33 deaths diectly linked to the outbreak, ten other people that ate canatloupes “related” to it died. A pregnant woman who fell ill from the outbreak suffered a miscarriage. Some 147 others were hospitalised.

“The filing of criminal charges in this deadly outbreak sends the message that absolute care must be taken to ensure that deadly pathogens do not enter our food supply chain,” said Patrick Holland of the FDA-Office of Criminal Investigations in Kansas City.

Both defendants have been charged with six counts of adulteration of a food and aiding and abetting. If convicted, each faces a maximum of a year in federal prison, and a fine of up to $250,000 per charge.

The trial date has been reportedly set for 2 December.