Three people have died after drinking milkshakes contaminated with Listeria bacteria from a restaurant in Tacoma, Washington, state health officials say.
Three others have been hospitalized, the Washington Department of Health said Friday.
Health investigators found the outbreak was linked to ice cream machines that were not cleaned properly at a Frugals restaurant in Tacoma, according to a release from the Washington State Department of Health.
Using genetic tracking, tests on the six individuals who were hospitalized between Feb. 27 and July 22 showed the bacteria inside the milkshakes was the same strain of Listeria that triggered the hospitalizations, the health department said.
While the restaurant stopped using its ice cream machines on Aug. 8, health officials warn that Listeria can sicken people up to 70 days later.
Listeria infection is a foodborne bacterial illness that can be very serious for pregnant women, people older than 65 and people with weakened immune systems, according to the Mayo Clinic.
All of the six who became ill had conditions that made their immune systems less able to fight disease.
Listeria is most commonly caused by eating improperly processed deli meats and unpasteurized milk products.
Listeria symptoms include:
- People who are not pregnant usually have a fever, muscle aches and tiredness. They may also get a headache, stiff neck, confusion, loss of balance, or seizures.
- Those who are pregnant also usually have a fever, muscle aches and tiredness. However, Listeria can cause pregnancy loss or premature birth. It can also cause serious illness or death in newborns.