Morel Mushroom Toxicity?

The Montana Department of Health and Human Services has released its final report on an outbreak of food-related illnesses including 2 deaths and 3 hospitalizations, and many more illnesses apparently of a gastrointestinal nature. The report finds the cases were definitively correlated with consumption of raw marinated morel mushrooms served in a restaurant dish, confirmed by DNA analysis to be Morchella sextelata cultivated in China. Symptoms were lessened in a batch where the mushrooms were presumably partially cooked because the marinade was near boiling when they were added, and no known cases are associated with fully cooked mushrooms from the lot distributed to other restaurants.

Screening for pesticides, heavy metals, bacterial toxins, and pathogens had no significant findings. The Montana Department of Health and FDA are now recommending that true morels are not edible raw, which I guess they weren’t before. The cause of the illnesses is not understood. Thoughts?


I and most mushroomers I know have for 40 years or more considered raw morels mildly toxic and require cooking. Don’t breathe in the fumes of the cooking morels!
A good rule of thumb is to cook all fungi you plan on consuming for at least ten minutes. Some edibles like boletes take longer for the flavor and texture to develop, past the noodle stage and lightly browned and nutty.
Some toxins cannot be removed by any means.
The North American Mycological Association, has a page on toxic fungi that is worth looking at. There is also a poisoning record.


Do you know what the toxin might be?

Initially it was thought that Gyromitrin/Monomethylhydrazine (found in false morels, Gyromitra etc.) was the toxin. Currently it is considered a hydrazine but is not fully understood.


Is it something where the concentration would vary a lot depending on like storage/handling/preparation or the specific samples? What I’ve heard is that this isn’t the first time that restaurant had some version of that dish, but obviously was the first time that there were multiple deaths and hospitalizations.

The amount of toxin does vary. Some toxins like the hydrazines are heat labile so adequate cooking removes the toxin, just don’t breathe the vapors.
In addition to the FDA suggestions I would add that the first time eating a mushroom only a small portion be consumed. Wait 24 hours and if no symptoms try a small amount more. Even properly prepared mushrooms can result in an allergic response in some individuals (think peanuts, strawberries etc.).


I take pictures of wild mushrooms sometimes but I’ve never tried eating one yet. I like that with wild berries the poisonous ones usually taste poisonous (this saved me once before I realized that elderberries are poisonous raw; they sure do taste like it). I do buy cultivated mushrooms from the farmers market sometimes (some of those are amazing!) and dried ones from the grocery store mainly for use in soup.

There are vanishingly few mushrooms that any forager will recommend eating raw. Outside of Fistulina hepatica and like, dried wood ear fungus, i almost never see it suggested.

This includes morels. I’d be willing to bet too that every one of my foraging books tells people to cook their mushrooms, especially morels.

This resteraunt screwed up bad, but i have no clue how Montana didnt already recommend against raw morels


The restaurant is claiming in a letter to a Bozeman newspaper that the FDA did not recommend against raw morels before. Maybe that is just untrue? The letter is awful and they really should have hired a crisis PR firm or something, my local sense is that that letter made many people much less sympathetic to their situation.

Edit: I’m pretty sure the actual investigation was almost completely federal from day 1 because of the initial apparent potential for a biosecurity/international relations angle of it involving Chinese imports; I’m sure the Montana ‘final’ report is really just summarizing the federal conclusions for public release. Weirdly, the incident got zero national coverage but almost every major UK paper covered it initially.


I wouldnt even know where to look to see if there was a guideline before the incident.

Ok so it looks like in 2014 a panel reccomended that the FDA should add the phrase ‘All mushrooms with the exception of truffles must be well cooked.’ to §§ 3-101.16 of their administrative guidelines covering use of specifically wild mushroom species. As far as I can tell that phraseology has not been adopted in the most recent available version of that paragraph.

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Well, so much for those white button mushrooms in salad…

Speaking of Agaricus bisporus look up agaritine and Paul Stamets. Draw your own conclusions.

Yes I think in context it is meant to refer to either cultivated or foraged specimens of wild species. However I suspect there is no way that phraseology would have passed copy editing checks without greater precision. if you’ve ever read any actual FDA/USDA promulgated regulations the level of precision is sometimes absolutely comical. Have you ever asked yourself, hmm, what is the difference between foods legally allowed to be labeled with the following terms?

  • Cheese Lasagna with meat
  • Lasagna with Meat and Sauce
  • Lasagna with Meat Sauce
  • Lasagna with Poultry
  • Lasagna with Tomato Sauce, Cheese, and Pepperoni
  • Meat Lasagna
  • Poultry Lasagna

Don’t worry, the USDA covers all that on page 91

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The UK press has a thing about poisonous mushrooms, venomous spiders and various other scare-worthy minor risks that they never actually personally encounter in their air-conditioned offices. The real risks like tick-borne Lymes disease or “rescue” dogs getting smuggled in from Romania without quarantine hardly ever get a mention.


It is a basic principle of toxicology, credited to Paracelsus: “All things are poison, and nothing is without poison; the dosage alone makes it so a thing is not a poison.”

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Here is the first direct public report I’ve seen of the specific symptoms of the woman who died in the newspaper today:

  • Went into cardiac arrest shortly after reaching hospital but was resuscitated
  • Went into liver and kidney failure
  • “Her throat hurt. Her body hurt,” he said. “You touched her skin and it was very tight. Think of a balloon that was at max pressure before it bursts. Her skin was leaking fluid because it was so tight.”

  • Eventually couldn’t breathe on her own and needed a ventilator
  • Died after 12 days
  • The other person who died died less than 24 hours after eating the mushrooms

That is… a nuts reaction. Liver failure sounds more like a reaction to amatoxins, the raw morel side effect I usually hear about is gastrointestinal distress - though obviously, that could be hearsay.

Also, English culture on the whole is a mycophobic culture, in contrast to the mycophilic French culture.

Regardless of what the FDA says, or doesnt say, you shouldn’t be serving wild sourced foods without knowing how to properly prepare them. Serving raw morels…