CHICAGO (NYTIMES) Tyson Foods is recalling nearly 8.5 million pounds (3.87 million kg) of frozen chicken that might have been contaminated with listeria, the US Department of Agriculture said.

The voluntary recall was issued after USDA investigators were notified last month about two people who had been sickened with listeriosis, the department said in a statement on Saturday (July 3).

An investigation found evidence linking those cases to frozen chicken from Tyson Foods, the agency said. Investigators eventually identified three cases linked to the recalled products, including one death, the department said.

Symptoms of listeriosis, an infection caused by the bacterium Listeria monocytogenes, include fever, convulsions, muscle aches and gastrointestinal issues, according to the USDA.

The recalled products were frozen, fully cooked chicken produced between December and April, the department said. The products include chicken strips, chicken pizza and pulled chicken breasts that were sold under brand names including Tyson, Jet’s Pizza and Casey’s General Store.

The packages have the “establishment code” P-7089 on them, the department said.

In a statement, Tyson Foods said the recalled products were produced at a plant in Dexter, Missouri. The company distributed the chicken to stores, hospitals, schools, restaurants and other locations, the department said.

“We’re committed to providing safe, healthy food that people rely on every day,” Scott Brooks, senior vice president for food safety and quality assurance at Tyson Foods, said in the statement.

“We are taking this precautionary step out of an abundance of caution and in keeping with our commitment to safety.”

The USDA said it would continue its investigation to determine if additional listeriosis cases were linked to the recalled products.

The department urged people to throw away or return the recalled chicken.

Pregnant women, adults over 65 and people with weakened immune systems are most susceptible to a serious case of listeriosis, according to the Centers for Disease Control and Prevention. Symptoms usually develop one to four weeks after eating food contaminated with listeria.

In May 2019, Tyson Foods significantly expanded a recall of frozen, ready-to-eat chicken strips to close to 5.4 million kg over contamination concerns, the US Department of Agriculture said at the time.

The Department’s Food Safety and Inspection Service said it was aware of six complaints from consumers who found pieces of metal in the product, Reuters reported.