SAN ANTONIO, Texas (Reuters) - Texas-based Blue Bell Creameries, which stopped production and distribution of ice cream to 25 states in April after the discovery of listeria bacteria, said on Friday that listeria was discovered again in a production facility.

The company did not specify in a statement in which of its three facilities listeria had been found but said that none was found in any of its ice cream. Blue Bell said it is moving to eliminate the bacteria through a “seek and destroy” process.

“We expect to periodically find microbiological indications in our facilities,” said Blue Bell, which declined comment beyond the statement. The company credited its “enhanced, robust testing system” for why it found the bacteria.

The company noted that because listeria is commonly found in the natural environment, “no manufacturer can ever assume it will be entirely eradicated.”

Blue Bell, ranked the No. 1 ice cream brand in the country in 2014, recalled all products last spring after 10 reported cases of listeria in four states were linked to Blue Bell frozen treats. Three of the people sickened, all hospital patients in Kansas, later died.

The disease, caused by eating food contaminated with listeria, primarily affects older adults, pregnant women, newborns and adults with weakened immune systems, according to the U.S. Centers for Disease Control and Prevention.

Blue Bell suspended production at its plants in Brenham, Texas; Broken Arrow, Oklahoma, and Sylacauga, Alabama last spring and said it conducted a major overhaul of production at all three plants.

Blue Bell laid off or furloughed hundreds of employees as a result of the shutdown.

Starting in November, the company began a phased process of returning its ice cream to store shelves. The company said the next phase of the process, in which ice cream will be distributed in Tennessee, Kentucky, the Carolinas, and Virginia, will proceed as planned.