Michigan wild mushroom safety

Even “edible” mushrooms need to be handled properly to prevent illness.

Although there is still snow on the ground and cold temperatures in the Upper Peninsula, many Michiganders are dreaming of wild mushroom harvesting, especially the coveted spring morels. Are you aware that some edible mushrooms can still make you sick? Of the 2,500 large, fleshy mushroom species in Michigan, only 60-100 of them are generally regarded as safe to eat. That sentence should make two questions come to mind:

  1. Why 60-100 and not an exact number?
  2. What does “generally” mean?

The answers to both those questions are related. “Generally” indicates that in most cases, the mushroom is consumed without ill effects if it was handled and cooked properly. However, there are always exceptions to rules and sometimes mushroom experts disagree on the likelihood of a particular mushroom causing illness. For example, true morels (Morchella spp.) are generally safe to eat as long as they have been cooked thoroughly. However, eating raw morels can cause gastric upset. Also, some individuals have allergies or intolerances for certain types of morels. For these reasons, morels are considered generally safe to eat, but should be consumed with caution the first time. Another example is the “chicken of the woods” or sulphur shelf (Letiporus sulfureus). The general edibility of this mushroom depends on what type of tree it is growing on. Typically, this species, if gathered from hardwood trees is edible, but those gathered from conifers or locusts are frequently toxic.

In Michigan, there are 50 species of large, fleshy mushrooms known to be toxic to humans. Levels of toxity vary between species and range from “deadly poisonous,” to “occasional gastric distress.” Several of the deadly species, especially those in the Amanita family, are extremely dangerous because symptoms don’t develop until six to 36 hours after ingestion, which is too late for the only antidote – a stomach pump. Another poisonous mushroom to be aware of this spring is the false morel, or beefsteak mushroom (Gyromitra esculenta). It is commonly mistaken for a true morel, and can have deadly results. Although some people have eaten this mushroom without illness, it usually causes vomiting diahrea and cramps, and can cause kidney failure and death. Poisonous mushrooms may also cause allergic-type reactions, or cause hallucinogenic reactions.

Michigan State University Extension recommends the following to avoid mushroom poisoning:

  • Never eat any mushroom unless you are positive about the identification of it
  • Cook all mushrooms thoroughly
  • Be careful the first time you eat a new mushroom – only consume a small amount and wait several hours to make sure there is no reaction
  • Save a small portion of any new mushroom consumed as it will be helpful to medical staff in the event it makes someone sick
  • Never try mushrooms that are not considered generally safe to eat.

For more information on edible mushrooms visit Midwest American Mycological Instruction or download “Don’t Pick Poison,” which is a great guide to poisonous mushrooms in Michigan.

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