A nationwide recall has been issued for frozen nutritional shakes linked to a deadly listeria outbreak, according to the Food and Drug Administration. The shakes were sold to hospitals and long-term care institutions, including nursing homes.

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 long-running listeria outbreak only recently linked to recalled frozen supplemental nutrition shakes has infected 38 people, killing 12, according to an update on Monday from federal and state health officials.

Here is what you need to know about the deadly listeria outbreak, including which products are being recalled.

An outbreak tied to listeria infections has been reported in 21 states, including Alabama, with 37 hospitalizations and 11 deaths nationwide.

A deadly listeria outbreak has resulted in a recall of frozen supplemental shakes used at long-term care facilities. The shakes were made by Prairie Farms Dairy Inc. based in Fort Wayne, Indiana, and were sold under the brands of Lyons ReadyCare and Sysco Imperial, the Food and Drug Administration.

The Food and Drug Administration has issued an urgent warning about a listeria outbreak linked to meal supplement shakes served in hospitals and long-term care facilities, including those in Florida.

Two Connecticut residents were infected by listeria connected to the supplemental milkshakes, but have since recovered.

Supplement shakes distributed to hospitals and long-term care facilities have been recalled due to possible listeria contamination that is also linked to 12 deaths. The Food and Drug Administration says the recall is being instituted by Lyons Magnus LLC, which is recalling 4 oz. Lyons ReadyCare and Sysco Imperial Frozen Supplemental Shakes.