Hundreds of frozen waffle products sold in leading retailers including Walmart and Target are being recalled because of possible contamination by the listeria bacteria, according to the manufacturer.

TreeHouse Foods said Friday that it issued a voluntary recall after discovering possible contamination during routing testing at its plant. It said the U.S. Food and Drug Administration and Canadian food regulators are aware of the recall.

Listeria infections can cause mild illness including fever and diarrhea or more serious problems. The illness is most dangerous to pregnant women, newborns, adults over 65 and people with weakened immune systems, according to the U.S. Centers for Disease Control.

— The Associated Press