Blue Bell Creameries recently detailed the likely causes of a listeria outbreak linked to its ice cream in a filing with federal authorities.
The Associated Press and KXAS-TV in Fort Worth reported that Blue Bell in February sent its findings to the U.S. Food and Drug Administration.
The company wrote that it could not identify a single source of listeria contamination at its Brenham, Texas, headquarters and speculated that the bacteria entered the facility from one of several potential sources and settled on numerous pieces of equipment.
The filing, however, blamed contamination in its Broken Arrow, Oklahoma, facility on a drainage system that likely carried listeria into a storage room that housed clean equipment for use in food production.
The company said that the drain and floor were replaced in the room following the outbreak, which is no longer used to store equipment.
Alabama officials also found listeria at a third Blue Bell plant in Sylacauga but not in ice cream produced at the facility.
All three plants were shut down last year amid a nationwide recall of Blue Bell products, which were blamed for 10 deaths in four states.
The company since reopened each facility and its ice cream is returning to store shelves, but the crisis led to layoffs of about half its workforce. Blue Bell also faces numerous lawsuits over the scandal.