(CNN)– Pilgrim’s Pride is recalling over 4.5 million pounds of fully cooked chicken products.

The chicken — in boxes of whole-grain breaded nuggets, patties, breakfast patties, tenderloins and popcorn-style varieties — may be contaminated with “extraneous materials,” the U.S. Department of Agriculture said.

The materials include plastic, wood, rubber and metal, the USDA said in a news release today.

The products were sold in stores under the Gold Kist Farms, Pierce and Sweet Georgia brands. A complete list of the recalled products is available on the USDA website (PDF).

The Waco, Texas, company shipped the products to grocery stores and institutions like schools nationwide, according to the USDA release, a reissue of a statement made earlier in the month. It’s unclear how the “extraneous materials” got into the chicken products.

The company learned about the problem after customers complained about finding plastic in the nuggets, and it let the government know on April 6. The USDA’s Food Safety and Inspection Service found that more chicken products were also contaminated. Today’s recall expands the initial recall from April 7.

There have been no confirmed reports of health problems related to the chicken products, the USDA said. Consumers who have a recalled product in their refrigerator or freezer are advised to throw it away or return it to where it was purchased.

If you have other questions, call the company at (800) 321-1470 or the USDA’s meat and poultry hot line at (888) 674-6854. The USDA’s “Ask Karen,” a virtual representative, is also available to answer food safety questions 24 hours a day at AskKaren.gov.

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