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

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,

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.

An ongoing Listeria outbreak has mostly affected people living in long-term care facilities and people who were already hospitalized prior to becoming sick from the infection.

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,

The supplemental shakes are labeled under the brands Lyons ReadyCare and Sysco Imperial and were sold to institutional customers, including hospitals and long-term care facilities, officials said.

Frozen supplemental shakes sold to hospitals and long-term care facilities in 21 states, including Florida, are making people sick and already have led to 12 deaths.

A listeria outbreak linked to frozen nutritional milkshakes is to blame for 12 deaths and dozens of hospitalizations, the U.S. Food and Drug Administration confirmed Monday following an investigation that spanned years.

Frozen shakes distributed in long-term facilities around the United States have been recalled due to potential listeria contamination. Lyons Magnus announced Feb. 22 that it had issued a recall for 4 oz. Lyons ReadyCare and Sysco Imperial Frozen Supplemental Shakes, which were manufactured by Prairie Farms Dairy, Inc.