Twelve deaths have been reported as part of an outbreak of Listeria monocytogenes infections linked to frozen supplemental shakes, the US Food and Drug Administration said Monday. At least 38 people in 21 states had been infected,

Frozen shakes sold to nursing homes and other institutions are being recalled after a listeria outbreak in 21 states that has caused 11 deaths, according to the Federal Food and Drug Administration.

The Food and Drug Administration is investigating a possible link between frozen supplemental shakes and a deadly listeria outbreak. The now-recalled shakes are typically sold to hospitals and nursing homes,