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Foraging for mushrooms? Here’s how to avoid becoming a poisoning statistic

by Timber Press on November 7, 2014

in Food

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All images: Steve Trudell

Guidelines to help you avoid the dark side of mushrooming from the authors of Mushrooms of the Pacific Northwest.

Ask most Americans or Canadians what proportion of mushrooms are poisonous and likely they will say it is high. This leads to the common perception that eating wild mushrooms is a risky business on par with being a movie stunt-person or jumping motorcycles over large canyons. Although it is certainly true that mushrooms can, and do, kill people, the data show that such occurrences are both rare and nearly always preventable. Nationwide, of the many calls to poison control centers in the U.S., only about one in 200 involves mushrooms and, of these, the vast majority involve incidents where there are no symptoms—usually a child was found chewing, handling, or even just looking at a mushroom and the parents panicked.

So who gets poisoned and why? The simplest answer is people who don’t know what they are doing eat mushrooms that they shouldn’t. Thus, if one invests a bit of time learning some basic mushroom identification and maintains a conservative attitude in deciding what to eat, mushroom-hunting and -eating (mycophagy) can be a perfectly safe and rewarding pastime.

Fertile ridges of pacific golden chanterelle (Cantharellus formosus).

Fertile ridges of the pacific golden chanterelle (Cantharellus formosus).

◊  There are no simple “rules of thumb” for recognizing poisonous mushrooms. The only reliable approach is to identify the mushroom species and see what the history of human consumption indicates about its edibility.

◊  Do not pick mushrooms from places where they could have become contaminated by garden chemicals, fallout from vehicle exhaust, or other pollution sources. Fungi often concentrate substances from the environment and these can be dangerous. For instance, in the wake of the Chernobyl nuclear power plant accident, mushrooms from many parts of Europe were found to contain high levels of radioactive cesium.

This one is a no-no. Death cap (Amanita phalloides) is common in the PNW, even in urban areas. Before collecting for the table, learn the features of this (and other) deadly mushrooms. Be particularly careful when collecting white mushrooms and those that have olive, greenish, or yellowish colors.

This one is a no-no. Death cap (Amanita phalloides) is common in the PNW, even in urban areas. Before collecting for the table, learn the features of this (and other) deadly mushrooms.

◊  Inspect every one of your mushrooms carefully to be certain they all are of the same kind and that they are in good fresh condition. Start this process in the field to avoid mixing collections or bringing home over-the-hill mushrooms. Many cases of “mushroom poisoning” in fact are food poisoning caused by bacteria on spoiled mushrooms. Save two or three good-condition specimens in the refrigerator for later inspection by experienced identifiers in the event of adverse effects (“one for the pot, one for the doctor”).

◊  Never eat a mushroom unless it is positively identified as edible by you or someone whose judgment you have good reason to trust. Remember that to one who knows little, nearly anyone can appear to be an expert. Maintain an attitude of healthy skepticism and use the same discerning approach for identifying experts that you would for identifying mushrooms.

Hard-to-find blue chanterelle (Polyozellus multiplex) occurs most frequently in old-growth forests. A good edible species, but because of its rarity, restraint is encouraged when collecting this beauty.

Hard-to-find blue chanterelle (Polyozellus multiplex) occurs most frequently in old-growth forests. A good edible species; however, because of its rarity, restraint is encouraged when collecting this beauty.

◊  Never eat mushrooms raw (for nutritional, as well as toxicity, reasons). Some contain toxins that are degraded by heat, plus cooking breaks down the cell walls and makes the nutritious cell contents available to our digestive systems.

◊  When trying a new species, eat only that one species and only a small amount, and then wait 24 to 48 hours before eating other mushrooms. Idiosyncratic reactions are possible with what are, for most people, good edible mushrooms. Keep this in mind when serving wild mushrooms to guests.

Most common in parks and landscaped areas, often associated with birches, Paxillus involutus should be strictly avoided as an edible mushroom.

Most common in parks and landscaped areas, often associated with birches, Paxillus involutus should be strictly avoided as an edible mushroom.

◊  Eat wild mushrooms in moderation. Some contain toxins that appear to accumulate in our bodies over time to a point where adverse effects manifest themselves. In addition, overeating of even good edible species can make you sick, because mushrooms can be difficult to digest.

◊  Use extra caution when collecting outside your usual hunting grounds, especially when you are far from home. What you think is the same mushroom might, in fact, not be.

◊  Above all, remember that no meal is worth ending your life. When in doubt, throw it out (or seek help from someone with more experience).

An excellent edible mushroom, Marasmius oreades is more commonly known as fairy-ring mushroom. We'll give you one guess why.

An excellent edible mushroom, Marasmius oreades is more commonly known as fairy-ring mushroom. We’ll give you one guess why.

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trudell_sSteve Trudell is affiliate professor in the College of Forest Resources and lecturer in the Biology Department at the University of Washington. He has been identifying and photographing mushrooms and studying their ecology for over 30 years. Steve belongs to the Mycological Society of America, North American Mycological Association, and International Mycorrhiza Society, writes for several mycological publications, and frequently serves as foray mycologist or invited lecturer for mycological societies and other nature groups. His research interests include the roles of fungi in forest nutrient cycling.

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ammirati_jJoe Ammirati is professor of biology and teaches mycology and botany at the University of Washington. His research focuses mainly on the classification and evolutionary relationships of the gilled fungi, particularly in the genus Cortinarius, but also includes mushroom biogeography and co-evolution, mushroom toxicity, and fungal diversity of arctic/alpine, boreal, and subalpine habitats. Joe is the scientific advisor to the Puget Sound Mycological Society and Pacific Northwest Key Council.

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Click image for a look inside this book:

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“Hold on to your hats, mushroom lovers! This beautifully illustrated guide presents descriptions and photographs of 460 of the region’s most conspicuous, distinctive, and ecologically important mushrooms.”—Chuckanut Reader

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