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A few reasons to cook the mushrooms you eat

Cathy's Lab - a slice of science pie for the mushroom minded

- Cathy Scott is Chief Science Officer at Everything Mushrooms; she handles all the mycelium! Cathy is also a tremendous cook and dedicated fungal fanatic. This little slice of our web space is dedicated to Cathy's experiments, recipies, and mushroom musings. Be sure to check this page regularly for updates on some of the exciting things happening "behind the scenes" in Cathy's Lab at Everything Mushrooms.


- posted September 30, 2013 


My friend and fellow employee here at EM, Jessica Hammonds - a foodie fungal fanatic, eats raw wood ears mushrooms. Just walking along a trail she will reach down and pick one off a log and pop it in her mouth like it was a wild blackberry. She likes them for their interesting texture, crunchy on the outside but jellylike on the inside, with almost no flavor except a hint of earthiness. Turns out that it is pretty common to eat raw wood ears in Asia, but this strange inclination did compel me to write about the rationale behind cooking all the mushrooms you eat.

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LEFT: Jessica cooks up some of our summer chanterelle bounty                RIGHT: Fresh chanterelles ready for the pan

1. Flavor: For most people, a mushroom sautéed in butter or oil until golden brown and finished with a little wine is going to look and taste far more yummy then an uncooked mushroom. Especially if you are new to the world of mushrooms... outside white buttons and portobellos. It is prudent to start your new mushroom taste adventures with perfectly cooked little morsels. Even slightly undercooked mushrooms can have a rubbery texture that can turn off the most adventurous eater.

2. Digestion: The cell walls of mushrooms can be difficult to digest, they might even give you a tummy ache, or more severe intestinal distress if eaten raw. Mushroom cell walls contain chitin, the same polysaccharide that makes the hard outer shells of insects and crabs. Chitin and other components of the cell wall can be made more digestible by cooking. A little heat not only can avert a potential tummy ache but also helps release the many beneficial nutrients locked inside the cells.


ABOVE: Cooking lion's mane and oyster mushrooms allows the body to get the most out of the benefitial nutrients and medicinal properties

3. Hydrazine and other compounds: A chemical derivative of hydrazine, a toxic compound, is present in some of mushrooms including the white button (Hashida, Hayashi et al. 1990). Hydrazine, an ammonia like liquid compound, is easily volatilized with a thorough sauté. Eating a few uncooked mushrooms usually won't make you sick, as evidenced by the compound being present in the white button mushrooms, which are commonly eaten raw. While the toxicity of the compound hydrazine (also a component of rocket fuel) is well understood, exactly what mushrooms contain hydrazine and in what volume, has not been well studied. It is only through mushrooms like the false morel, which contain large amounts of the hydrazine gyromitrin, do we appreciate the toxic effects. It is clear that some people are more sensitive to hydrazine, while some feel no effect from eating false morels, others have become very sick or have even ceased to exist. Symptoms are usually gastrointestinal and neurological and most often occur within 6-12 hours of consumption. There is also evidence that repeated consumption can increase risk of illness. This has lead some scientists to believe some people may be deficient in enzymes that convert hydrazine to non-toxic compounds in the body (Coulet and Guillot 1982). If you always cook your mushrooms you will never need to know if you are sensitive to the hydrazine. 

In rare cases, individuals have developed a skin rash from eating raw or undercooked shiitake mushrooms. The shiitake sensitivity is an allergic reaction rather than a toxicity (Kopp, Mastan et al. 2009). However the lesson is the same-- when trying new mushrooms, cook mushrooms thoroughly. Mushrooms, like the false morel, are parboiled before consumption. Still if you really want to try mushrooms raw, eat only a small piece and wait for a possible reaction before eating a larger quantity.

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LEFT: Fresh morel mushrooms await a bath in breading and butter!           RIGHT: Cooking shiitake can help prevent potential allergic reactions

4. Bugs, bacteria and worms: Like most living things mushrooms can harbor bugs, bacteria or small worms like nematodes. Almost all are innocuous little buggers but to be on the safe side you can kill any stragglers with a good cooking. Mushrooms that grow on animal manure are the exception. They can harbor serious pathogens like tapeworms, E. Coli H7:O157, or listeria. White button mushrooms and portabellos are grown on composted manure which is meant to kill any lurking buggies, there have been cases where pathogenic bacteria survived this process (Viswanath, Murugesan et al. 2013). All the mushroom kits we sell here at Everything Mushrooms are wood eaters, and human pathogens are unlikely to be hanging out on wood, so you are safe from illness in that respect. There is a very small chance any mushrooms grown outside could be contaminated by a flying insect. Because tiny worms and bacteria can integrate into the mushroom as it grows it is unlikely a good washing will remove all hitchhikers. Even if the chance of a serious health threat is low the idea of eating little squirmies is enough for me to always cook mushrooms.

5. Fungal Infection: In extremely rare cases fruiting fungi have been know to infect immune comprised people (Speller and Maciver 1971; Kern and Uecker 1986). Although most of these fungi are soil inhabitants that infect through wounds, it is likely that all fungi can potentially be harmful to a damaged immune system. These fungi can be more aggressive than the obligate pathogens we are use to, and they can be inordinately difficult to treat. Luckily most of our immune systems will easily take care of those wayward mushroom spores and active mycelium that enter our bodily kingdom. However if you are diabetic, in treatment for cancer, have had an organ transplant or a serious disease like AIDS... you definitely will want to inactivate live mushroom tissue by thoroughly cooking.

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LEFT: Sliced and sautéed lion's mane mushrooms with veggies               RIGHT: Oyster mushrooms getting close to risotto

Traditional cooking methods like sauté, roasting, baking or boiling your mushrooms are the safest methods for eating mushrooms. Other methods like drying mushrooms are better than eating them raw but aren't foolproof. Pickled mushrooms are prone to botulism but are otherwise generally safe if done properly.

Science Lesson: You may have heard somewhere along the line that we are more closely related to fungus than plants. Fungi are one of the steps on the evolutionary road from algae to animals... plants veered off on a different route. Some had theorized this was the case by comparing physical traits fungi have in common with the animal kingdom, like chitin cell walls. More recently genetic relationship studies have validated the evolutionary tie between fungi and animals. Our evolutionary kinship is also the reason fungal infections can be very difficult to treat. The fungal metabolism is so similar to ours, it is very difficult to target a fungus without gravely affecting the human host as well.


Coulet, M. and J. Guillot (1982). "POISONING BY GYROMITRA - A POSSIBLE MECHANISM." Medical Hypotheses 8(4): 325-334.

Hashida, C., K. Hayashi, et al. (1990). "Quantities of agaritine in mushrooms (Agaricus bisporus) and the carcinogenicity of mushroom methanol extracts on the mouse bladder epithelium." [Nihon koshu eisei zasshi] Japanese journal of public health 37(6): 400-405.

Kern, M. E. and F. A. Uecker (1986). "MAXILLARY SINUS INFECTION CAUSED BY THE HOMOBASIDIOMYCETOUS FUNGUS SCHIZOPHYLLUM-COMMUNE." Journal of Clinical Microbiology 23(6): 1001-1005.

Kopp, T., P. Mastan, et al. (2009). "Systemic allergic contact dermatitis due to consumption of raw shiitake mushroom." Clinical and Experimental Dermatology 34(8): E910-E913.

Speller, D. C. E. and A. G. Maciver (1971). "ENDOCARDITIS CAUSED BY A COPRINUS SPECIES - FUNGUS OF TOADSTOOL GROUP." Journal of Medical Microbiology 4(3): 370-&.

Viswanath, P., L. Murugesan, et al. (2013). "Incidence of Listeria monocytogenes and Listeria spp. in a small-scale mushroom production facility." Journal of Food Protection 76(4): 608-615.