Foodborne outbreak of listeriosis associated with restaurant milkshakes in Pierce County

Actions requested

• Be aware of a Listeria monocytogenes (L. monocytogenes) outbreak associated with consuming milkshakes from the Frugals restaurant in Tacoma, Washington.  
• Consider listeriosis in high-risk individuals (aged 65 years or older, immunocompromised, or pregnant) who consumed contaminated milkshakes from the Frugals restaurant in Tacoma prior to August 8, 2023.
• Listeriosis has an estimated incubation period of 3-70 days (median of 3 weeks) and clinical presentation may vary by different risk groups:
• Individuals aged >65 years and people with immunocompromising conditions – most common clinical presentations are invasive infections such as sepsis, meningitis and meningoencephalitis; people can also experience focal infections, including septic arthritis, osteomyelitis, prosthetic graft infections, and infections of sites inside the chest and abdomen or of the skin and eye. 
• People who are pregnant– typically a relatively mild "flu-like" illness. Some pregnant people with Listeria infection have no symptoms. Rarely, severe disease can result in miscarriage, stillbirth, preterm labor, and sepsis or meningitis in the neonate.
• Immunocompetent – rarely develop invasive infections. May experience a self-limited acute febrile gastroenteritis following a high-dose Listeria exposure.
• Order laboratory testing if clinical history suggests listeriosis.
• Forward L. monocytogenes positive specimens to the Washington State Public Health Laboratory for serotyping and whole genome sequencing (WGS).
• Routinely advise patients aged >65 years, people with immunocompromising conditions, pregnant people and newborns, on how they can choose safer foods to protect their health or their pregnancy.
• Avoid unpasteurized dairy products, unheated deli meat, cold cuts, hot dogs, and fermented or dry sausages, premade deli salads (e.g., coleslaw and potato, tuna, or chicken salads), raw or lightly cooked sprouts, refrigerated smoked fish, refrigerated pâté or meat spreads, and cut melon (if left out for more than 2 hours or in the refrigerator for more than a week).
• In the last few years, listeriosis outbreaks have been associated with certain pasteurized frozen desserts like ice cream (hard and soft serve), packaged salads, and raw enoki mushrooms.
• Report suspected listeriosis cases associated with this outbreak to Public Health at (206) 296-4774 within 24 hours.