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,

A listeria outbreak linked to recalled 4 oz. Lyons ReadyCare and Sysco Imperial Frozen Supplemental Shakes has left 12 people dead, according to the U.S. Food and Drug Administration (FDA).

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.

Supplemental shakes have been linked to a deadly listeria outbreak. They were distributed in hospitals and long-term care facilities.

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.

Recalled shakes were sent to nursing homes and hospitals. No San Diego County cases have been reported so far.

In the outbreak, 38 people were infected across 21 states, including Pennsylvania, the FDA said. Most of them lived in long-term care facilities or were hospitalized prior to getting sick.