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,

The U.S. Food and Drug Administration (FDA) is working together with the Centers for Disease Control and Prevention (CDC) in collaboration with state and local partners to investigate illnesses in a multi-state outbreak of Listeria monocytogenes infections.

An ongoing listeria outbreak credited with 11 deaths is linked to frozen supplemental shakes. Here’s what you should know: What shakes have been recalled and where did they go? The shakes, sold in 4-ounce cartons under the brands Lyons ReadyCare and Sysco Imperial,