The FDA’s announcement this week that it had identified the source of an enoki mushroom Listeria outbreak was a breakthrough in an investigation that has seemed dormant for months. But it was also something of a headscratcher.
On January 17, the U.S. Food and Drug Administration (FDA) announced that enoki mushrooms imported from China and distributed in the U.S. by Utopia Foods, Inc. of Glendale, NY were the source of the outbreak. The significant development in the investigation was a long time coming. It was the first outbreak update the agency has issued since late November 2022. But the weird thing was Utopia enoki mushrooms were recalled for Listeria last month.
The recall, issued on December 13, 2022, stated that the problem was discovered during routine sampling conducted in the State of Missouri. At the time, all Utopia enoki mushrooms were supposed to be removed from commerce. But one month later Utopia issued a recall expansion for enoki mushrooms with the same bar code number that were distributed from January 6 to January 13, 2023. The expanded recall did not mention additional product testing.
So, why was FDA naming Utopia enoki mushrooms the source of the outbreak a month after they had been recalled for Listeria?
The answer is there is so much Listeria on these (and other) enoki mushrooms. Let’s walk through it from the beginning.
November 17 was a Big Day
On November 17, 2022, Green Day Produce of Vernon, CA issued an enoki mushroom Listeriarecall. The Michigan Department of Agriculture and Rural Development (MDARD) discovered the problem after collecting and analyzing a retail sample that tested positive for Listeria.
These mushrooms were sold from September 2022 – October 2022. But they should never have been on store shelves in the first place as they were imported from Korea where a country-wide ban on enoki mushrooms has been in place since July 2022. The ban was put in place due to the high number of enoki mushrooms that continued to test positive for Listeria after they were linked to a deadly outbreak in 2020.
Also on November 17, 2022, the Centers for Disease Control and Prevention (CDC) announced an enoki mushroom Listeria outbreak that had sickened two people. The announcement said a recall had not been issued in conjunction with the outbreak and it did not state which country produced the mushrooms associated with the illnesses.
The CDC stated that genetic tests had been used to identify the “fingerprint” of the Listeria strain cultured from the outbreak patients. And that in November 2021, FDA found Listeria with this fingerprint in one sample of enoki mushrooms collected at import. “However, to date, the firm associated with this sample has not been identified as a potential source of enoki mushrooms in this outbreak,” the agency stated in November.
This morning the FDA confirmed to Food Poisoning Bulletin that this company was not Utopia.”The 2021 FDA import sample is not a Utopia product and not related to the Utopia recall. The exporter of the 2021 sample did not appear in FDA’s traceback into the supply chain of product consumed by ill people in this outbreak.”
On November 22, 2022, the CDC issued a short update saying the Listeria found in the Green Day enoki mushrooms did not match the outbreak strain and was not linked to any reported illnesses in the U.S.
So, on the day the outbreak was announced, a Listeria recall was issued for one company’s mushrooms that had been illegally distributed during the window of time the patients got sick, and another company’s mushrooms had previously tested positive for the specific Listeria strain linked to the outbreak. Yet, neither brand would end up being the source of the outbreak. And until a couple of days ago it didn’t seem like Utopia would be either.
The Utopia Recalls
The FDA tried to clear up confusion about the Utopia recalls by issuing a lengthier investigation update on January 18. The agency explained that through routine sampling it recently found the outbreak strain of Listeria and a second Listeria strain in a sample of Utopia brand enoki mushrooms collected at import. Genetic tests showed the second strain was linked to one illness.
So, that’s three distinct strains of Listeria cultured from Utopia enoki mushrooms within a month. The December strain, which was not linked to any illnesses, the initial outbreak strain linked to two illnesses, and a second outbreak strain linked to one illness.
And Utopia is not alone. Enoki mushrooms were the most-recalled food of 2022. There were 11 recalls, all of them for Listeria.
Symptoms of a Listeria infection include high fever, severe headache, stiff neck, other muscle stiffness, confusion, loss of balance, and convulsions. These symptoms can develop within 24 hours of exposure to contaminated food. But sometimes they can take as long as 70 days to develop.
More than 90 percent of people with Listeria require hospitalization and about 20 percent of cases are fatal. Pregnant women, who can suffer miscarriage or stillbirth if they contract Listeria, account for about one-sixth of all cases.