Newly released documents show some early evidence of problems at Blue Bell Creameries' plants in Texas and Oklahoma.
The documents released Thursday by the U.S. Food and Drug Administration contained results of 2009 and 2012 inspections of the plants. Some of the problems inspectors found included condensation dripping into containers before they were filled with ice cream and residue on some food receptacles.
Texas-based Blue Bell has shut down and recalled all products after listeria in its products was linked to three deaths.
According to results released earlier this month from an FDA investigation, Blue Bell knew there was listeria in the Oklahoma plant from private testing as far back as two years ago.
The FDA said Blue Bell had not notified the government about the listeria findings. Companies are only required to report to the FDA if they find a "reasonable probability" that a food could make people sick.
Blue Bell spokesman Joe Robertson said the company is in the midst of a review of all of its cleaning and procedures "to help give regulatory agencies and the public confidence that when our products return to market, they will be safe."
Listeria generally only affects the elderly, people with compromised immune systems, and pregnant women and their newborn infants. It can cause fever, muscle aches and gastrointestinal symptoms and can be fatal. It also can cause miscarriage, stillbirth, premature labor, and serious illness or death in newborn babies.