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,

Recalled supplemental shakes were distributed to hospitals and long-term care facilities nationwide, federal officials say.

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,