Nearly 700 frozen waffle products, some of them sold under the brands of major retailers such as Kroger, Target and Walmart, were recalled Friday over concerns of potential contamination with the bacteria Listeria monocytogenes, according to their manufacturer.

The manufacturer, TreeHouse Foods, issued a voluntary recall and said in a statement that the “issue was discovered through routine testing at the manufacturing facility.”

There have been no confirmed reports of illness TreeHouse said.,

TreeHouse, which operates more than two dozen production facilities in the United States and Canada, said the recall affected products distributed in both countries.

Frozen waffle brands affected by the recall included several of Kroger’s Simple Truth protein waffles, Target’s Good & Gather Homestyle and Buttermilk flavors, and Walmart’s Great Value Homestyle and Blueberry waffles. — The New York Times