(WTVO) — Frozen shakes sold to nursing homes and other institutions are being recalled after a listeria outbreak in 21 states that has caused 11 deaths, according to the Federal Food and Drug Administration.

The shakes have made at least 38 people ill, with 37 hospitalizations, the FDA said Friday.

Frozen supplemental shakes under the brands Sysco Imperial and Lyons ReadyCare have been voluntarily recalled, the FDA said. The shakes were primarily given to hospital patients and long-term care patients.

States with cases include Alabama, California, Colorado, Connecticut, Florida, Illinois, Indiana, Maryland, Michigan, Minnesota, Missouri, North Carolina, Nevada, New York, Ohio, Oklahoma, Pennsylvania, Tennessee, Texas, Washington and West Virginia.

The outbreak dates to 2018 but has persisted through 2025, including 20 cases from 2024 to 2025, according to the Centers for Disease Control and Prevention. Investigators had been previously unable to identify the source.

Symptoms of listeria infection include fever, muscle aches, nausea, tiredness, vomiting, and diarrhea. In more severe cases, symptoms may include headache, stiff neck, confusion, loss of balance, and convulsions.

“Listeria can survive in refrigerated temperatures and can easily spread to other foods and surfaces,” the FDA stated.

The FDA’s investigation is ongoing.