The FDA has closed its investigation into an outbreak of Listeria monocytogenes infections traced to supplemental shakes served in medical facilities. A total of 42 people were sickened in the outbreak, with 14 deaths reported.

The Food and Drug Administration said in its final outbreak updat that all 42 of the patients had required hospitalization. The agency, with the Centers for Disease Control and Prevention, had been investigating the outbreak since Nov. 25, 2024. By the end of the outbreak, patients in 21 states had been identified. According to the CDC, the recent investigation showed the outbreak dates back to 2018.

The source of the Listeria was traced to Lyons ReadyCare brand and Sysco Imperial brand frozen supplemental shakes manufactured by Prairie Farms from the Prairie Farms Dairy facility in Fort Wayne, IN.

The FDA’s traceback investigation identified that each of the long-term care facilities who supplied invoice information for review from 2024 to present received frozen supplemental shakes of either Lyons ReadyCare or Sysco Imperial brand.

As part of the investigation, the FDA conducted an onsite inspection and collected environmental and product samples at Prairie Farms Dairy Inc. in Fort Wayne, IN. Three of the environmental swabs collected from the processing area tested positive for Listeria monocytogenes. Whole Genome Sequencing analysis determined that the Listeria detected in the samples was the strain of Listeria that caused illnesses in the outbreak.

In response to the outbreak investigation, Lyons Magnus LLC voluntarily recalled 4-ounce Lyons ReadyCare and Sysco Imperial frozen supplemental shakes with best-by dates of Feb. 21, 2025, through Feb. 21, 2026. At this time, no recalled frozen supplemental shakes should be available on the market, according to the FDA.

about Listeria infections
Food contaminated with Listeria monocytogenes may not look or smell spoiled but can still cause serious and sometimes life-threatening infections. Anyone who has eaten any of the recalled products and developed symptoms of Listeria infection should seek medical treatment and tell their doctors about the possible Listeria exposure.

Also, anyone who has eaten any of the recalled products should monitor themselves for symptoms during the coming weeks because it can take up to 70 days after exposure to Listeria for symptoms of listeriosis to develop. 

Symptoms of Listeria infection can include vomiting, nausea, persistent fever, muscle aches, severe headache, and neck stiffness. Specific laboratory tests are required to diagnose Listeria infections, which can mimic other illnesses. 

Pregnant women, the elderly, young children, and people such as cancer patients who have weakened immune systems are particularly at risk of serious illnesses, life-threatening infections, other complications and death. Although infected pregnant women may experience only mild, flu-like symptoms, their infections can lead to premature delivery, infection of the newborn, or even stillbirth.