Outbreak Investigation Updates by Date

Posted April 17, 2020 at 3:00 PM ET

April 8, 2020

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Since the last update on March 27, no additional illnesses have been reported.

As of April 8, 2020, 36 people infected with the outbreak strain of Listeria monocytogenes have been reported from 17 states. A list of the states and the number of cases in each can be found on the Map of Reported Cases page.

Listeria was identified in ill people’s samples from November 23, 2016, to December 13, 2019. Ill people range in age from less than 1 to 97 years, with a median age of 67. Fifty-eight percent of ill people are female. Of 32 ill people with information available, 30 hospitalizations have been reported. Four deaths have been reported from California, Hawaii, and New Jersey. Six cases are pregnancy-associated and two resulted in fetal loss.

Investigation of the Outbreak

Epidemiologic, traceback, and laboratory evidence indicates that enoki mushrooms labeled as “Product of Korea” are the likely source of this outbreak.

State and local public health officials interviewed ill people about the foods they ate in the month before they became ill. Twelve out of 22 (55%) reported eating mushrooms, including enoki, portobello, white, button, cremini, wood ear, maitake, and oyster.

FDA collected samples of enoki mushrooms at import from Green Co. of the Republic of Korea for testing. On April 6, testing results showed that two samples yielded the outbreak strain of Listeria monocytogenes. As a result, on April 7, Green Co. was placed on Import Alert 99-23external icon and H&C Foods Inc. recalled enoki mushrooms supplied by Green Co.

On March 10, the California Department of Public Health collected enoki mushrooms for testing from grocery stores. Testing identified Listeria monocytogenes in one sample, and whole genome sequencing is being conducted to determine if the Listeria in these recalled mushrooms is the same as the outbreak strain. These mushrooms are labeled as “Product of Korea” and were distributed by Guan’s Mushroom Co. On March 23, Guan’s Mushroom Co. recalled its enoki mushrooms.

On February 25, the Michigan Department of Agriculture and Rural Development collected mushrooms for testing from a grocery store where an ill person purchased enoki mushrooms. Two samples of enoki mushrooms yielded the outbreak strain of Listeria monocytogenes. These mushrooms are labeled as “Product of Korea” and were distributed by Sun Hong Foods, Inc. On March 9, Sun Hong Foods, Inc. recalled its enoki mushrooms.

Consumers, food service operators, and retailers should not eat, serve, or sell recalled enoki mushrooms.

On March 18, the Korean Ministry of Food and Drug Safety issued a press release about their investigation findings. They detected Listeria monocytogenes in enoki mushrooms produced by two firms in Korea.

CDC is concerned that enoki mushrooms from Korea (Republic of Korea) may be contaminated with Listeria monocytogenes. We are advising people who are more likely to develop a Listeria infection – pregnant women, adults age 65 or older, and people with weakened immune systems – to avoid eating any enoki mushrooms from Korea, until investigators determine the source of contamination and if additional products are linked to illness.

CDC will provide updates when more information is available.

March 27, 2020

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Since the last update on March 10, there have been no additional illnesses reported.

As of March 26, 2020, 36 people infected with the outbreak strain of Listeria monocytogenes have been reported from 17 states. A list of the states and the number of cases in each can be found on the Map of Reported Cases page.

Listeria was identified in ill people’s samples from November 23, 2016, to December 13, 2019. Ill people range in age from less than 1 to 97 years, with a median age of 67. Fifty-eight percent of ill people are female. Of 32 ill people with information available, 30 hospitalizations have been reported. Four deaths have been reported from California, Hawaii, and New Jersey. Six cases are pregnancy-associated and two resulted in fetal loss.

Investigation of the Outbreak

Epidemiologic, traceback, and laboratory evidence indicates that enoki mushrooms labeled as “Product of Korea” are the likely source of this outbreak.

State and local public health officials interviewed ill people about the foods they ate in the month before they became ill. Twelve out of 22 (55%) reported eating mushrooms, including enoki, portobello, white, button, cremini, wood ear, maitake, and oyster.

On March 10, 2020, the California Department of Public Health collected enoki mushrooms for testing from grocery stores. Testing identified Listeria monocytogenes in one sample and whole genome sequencing is being conducted to determine if the Listeria in these recalled mushrooms is the same as the outbreak strain. These mushrooms are labeled as “Product of Korea” and were distributed by Guan’s Mushroom Co. On March 23, 2020, Guan’s Mushroom Co. recalled its enoki mushrooms.

On February 25, 2020, the Michigan Department of Agriculture and Rural Development collected mushrooms for testing from a grocery store where an ill person purchased enoki mushrooms. Two samples of enoki mushrooms yielded the outbreak strain of Listeria monocytogenes. These mushrooms are labeled as “Product of Korea” and were distributed by Sun Hong Foods, Inc. On March 9, 2020, Sun Hong Foods, Inc. recalled its enoki mushrooms.

Consumers, food service operators, and retailers should not eat, serve, or sell recalled enoki mushrooms.

FDA is working to determine if other distributors in the United States received the same enoki mushrooms.

On March 18, 2020, the Korean Ministry of Food and Drug Safety (MFDS) issued a press release about their investigation findings. They detected Listeria monocytogenes in enoki mushrooms produced by two firms in Korea.

CDC is concerned that enoki mushrooms from Korea (Republic of Korea) may be contaminated with Listeria monocytogenes. We are advising people who are more likely to develop a Listeria infection – pregnant women, adults age 65 or older, and people with weakened immune systems – to avoid eating any enoki mushrooms from Korea, until investigators determine the source of contamination and if additional products are linked to illness.

CDC will provide updates when more information is available.

March 10, 2020

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CDC, public health and regulatory officials in several states, and the U.S. Food and Drug Administration (FDA) are investigating a multistate outbreak of Listeria monocytogenes infections linked to enoki mushrooms.

Public health investigators are using the PulseNet system to identify illnesses that may be part of this outbreak. PulseNet is the national subtyping network of public health and food regulatory agency laboratories coordinated by CDC. DNA fingerprinting is performed on Listeria bacteria isolated from ill people by using a standardized laboratory and data analysis method called whole genome sequencing (WGS). CDC PulseNet manages a national database of these sequences that are used to identify possible outbreaks. WGS gives investigators detailed information about the bacteria causing illness. In this investigation, WGS showed that bacteria isolated from ill people were closely related genetically. This means that people in this outbreak are more likely to share a common source of infection.

As of March 9, 2020, 36 people infected with the outbreak strain of Listeria monocytogenes have been reported from 17 states. A list of the states and the number of cases in each can be found on the Map of Reported Cases page.

Listeria samples from ill people were collected from November 23, 2016 to December 13, 2019. Ill people range in age from less than 1 to 97 years, with a median age of 67. Fifty-eight percent of ill people are female. Of 32 ill people with information available, 30 hospitalizations have been reported. Four deaths have been reported from California, Hawaii, and New Jersey. Six cases are pregnancy-associated and two resulted in fetal loss.

Investigation of the Outbreak

Epidemiologic and laboratory evidence indicates that enoki mushrooms labeled as “Product of Korea” are the likely source of this outbreak.

State and local public health officials interviewed ill people about the foods they ate in the month before they became ill. Twelve out of 22 (55%) reported eating mushrooms, including enoki, portobello, white, button, cremini, wood ear, maitake, and oyster.

Michigan Department of Agriculture and Rural Development collected mushrooms for testing from a grocery store where an ill person purchased enoki mushrooms. Two samples of enoki mushrooms yielded the outbreak strain of Listeria monocytogenes. These mushrooms are labeled as “Product of Korea” and were distributed by Sun Hong Foods, Inc. Additional product testing is ongoing in California.

On March 9, 2020, Sun Hong Foods, Inc. recalled enoki mushrooms (UPC 7 426852 625810) labeled as “Product of Korea”. Consumers, food service operators, and retailers should not eat, serve, or sell recalled enoki mushrooms. Enoki mushrooms distributed by Sun Hong Foods, Inc. do not account for all illnesses in this outbreak. FDA is working to identify the source of the enoki mushrooms distributed by Sun Hong Foods, Inc. and determine if other distributors received the same enoki mushrooms.

CDC is concerned that enoki mushrooms labeled as “Product of Korea” may be contaminated with Listeria monocytogenes and are advising people at higher risk – pregnant women, adults ages 65 years or older, and people with weakened immune systems – to avoid eating any enoki mushrooms labeled as “Product of Korea”, until investigators determine the source of contamination and if additional products are linked to illness.

CDC will provide updates when more information is available.