The frozen supplemental drinks have been linked to an outbreak of listeria that has killed at least 11 people and hospitalized 37.

A Listeria outbreak linked to recalled frozen shakes has killed 11 people, raising concerns about food safety oversight in nursing homes and hospitals.

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.