Authorities Investigating Listeria Outbreak Linked To Enoki Mushrooms

A listeria outbreak has sickened people in two states, though it may not be limited to these locations. The investigation has so far linked the illnesses to enoki mushrooms.

Public health officials are investigating an active listeria outbreak linked to enoki mushrooms. These are the ones that are white and have thin stems that are often used in soups, stir-fried dishes and hot pots, the U.S. Centers for Disease Control and Prevention (CDC) noted in its announcement.

So far, two people have fallen ill and have had to be hospitalized in the outbreak, one of whom is from Michigan while the other is from Nevada.

An event is considered a food-borne disease outbreak when "two or more people get the same illness from the same contaminated food or drink," according to the CDC. It's worth noting that the number of people who get sick and the affected states may not be limited to the ones already reported.

"(T)he true number of sick people in this outbreak is likely higher than the number reported," the agency noted. "This is because some people recover without medical care and are not tested for Listeria."

Enoki mushrooms that are contaminated with listeria are behind the illnesses in the outbreak, data shows. Both patients said they consumed enoki mushrooms or dined at restaurants with menu items that have enoki mushrooms. Furthermore, whole genome sequencing (WGS) showed that the samples from the two patients were "closely related genetically," suggesting that they got sick from the same source.

However, authorities are still identifying the specific brands that may be linked to the outbreak.

The CDC is urging people to warn their friends and relatives for whom a listeria infection may be "especially harmful." These include those with weakened immune systems, those who are 65 years old or older and those who are pregnant, in whom a listeria infection may be mild but can cause complications such as pregnancy loss, premature birth or severe infection in the newborn.

"If you are in any of these groups, do not eat raw enoki mushrooms," the CDC warned. "Cook enoki mushrooms thoroughly to kill any foodborne germs."

The CDC first investigated a listeria outbreak linked to enoki mushrooms in the U.S. in 2020, and officials have collected mushroom samples for testing since, the agency noted. This has led to 20 recalls of the mushroom.