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.

Listeria-tainted frozen shakes served at hospitals and long-term care facilities have sickened at least 38 people and resulted in the deaths of 12, the Food and Drug Administration said. The FDA’s investigation is ongoing.