Health inspectors found widespread contamination and “poor sanitary practices” at the Colorado farm that produced tainted cantaloupes linked to the deadliest U.S. foodborne illness outbreak in more than a quarter-century.

A packing facility owned by Jensen Farms in Granada, Colorado, tested positive for the strains of listeria that have sickened 123 people in 26 states, killing 25, the Food and Drug Administration told the company in a warning letter posted today on the agency’s website.

The outbreak prompted Jensen Farms to recall the contaminated fruit on Sept. 14. The tainted melons have caused more deaths than any foodborne illness in the last 25 years, Barbara Mahon, deputy chief of the Centers for Disease Control and Prevention’s Enteric Disease branch, said today on a conference call.