For foodies and naturalists alike, foraging for wild mushrooms offers a flavorful foray into the wilderness. But there’s danger as well: just this month, poison mushrooms killed three people in California and sickened three others, in a potent reminder that it’s important to exercise caution before cooking a late autumn fungus harvest.
Scientists have identified at least 1,000 different types of wild fungi in the Chicago region alone, according to mycologist Gregory Mueller, who with Joe McFarland co-authored the book “Edible Wild Mushrooms of Illinois and Surrounding States.” But only a tiny fraction of that number have been found edible, the authors note.
It’s hard to tell poisonous mushrooms apart from non-poisonous ones, though. And that’s why mushroom hunters should find a mycologist after finding their fungi.
The truth is, Mueller said, most mushroom poisoning cases involve incidents in which curious individuals – typically children – pluck and eat fungi while exploring their backyards. “We get lots of young children” throughout the year, the mycologist noted.
But adults often fall into the same trap during the mushrooming season, said Connie Fischbein, a mushroom expert at the Illinois Poison Center.
“They see something they think looks good, they take it home and cook it, and they get sick. They haven’t spoken to a mycologist or someone who knows mushrooms to get it identified,” Fischbein said.
In Illinois, there are “probably seven different major mushroom toxin groups” and “only four or five” that are potentially fatal, Mueller said. While there are no current statistics in Illinois regarding the number of people who reported ingesting a poisonous mushroom, Mueller said, he’s heard anecdotal reports that as of several years ago, there were “somewhere between 300-400 cases a year.”
While most of those turned out to be false alarms, "there’s a fair amount of people who end up getting sick – mostly stomach upset,” said Mueller, who is also former curator of fungi at the Field Museum of Natural History and once served as president of the Mycological Society of America.
Mueller has never seen a mushroom-related death in the 28 years he’s worked in Chicago. However, the North American Mycological Association said it receives an average of one report a year regarding a mushroom-related death. Their most recent data available online stated that four people died from eating poisonous mushrooms in 2009. The most serious incidents involved people who who consumed mushrooms that contain the deadly toxic compound amatoxin.
Amatoxins are a subgroup of at least eight toxic compounds found in several different types of poisonous mushrooms. They are present in the genus Amanita (a species of all-white mushrooms known as “the destroying angel” because they are fatally toxic), as well as the Lepiota and Galerina species.
Amatoxins can cause irreversible liver and kidney damage. Their toxicity is so great that patients who have consumed amatoxins usually can’t survive without a liver transplant, Fischbein said.
Although it’s rare, the Illinois Poison Center’s Fischbein said, she has received several calls in the last three years from people who’ve been exposed to amatoxin-containing mushrooms. But she said that she’s more likely to hear of non-deadly mushroom consumptions cases than deadly ones.
“There’s a very common mushroom called Chlorophyllum molybdites, commonly known as the false parasol or green-spored parasol, that commonly grows throughout the summer months,” Fischbein said. “It’s a very common cause of mushroom poisoning – I think the most common one in Illinois and in North America.“
But it’s less deadly. Chlorophyllum molybdites cause vomiting, nausea and diarrhea, as do Omphalotus olearius (the “jack o'lantern”), which Fischbein said foragers often mistake for the edible Chantarelle.
All this raises a question for consumers, particularly those who are part of the growing sustainable food scene in which organic and foraged produce are featured recipe ingredients: should gastrophiles steer clear of food stands at farmers’ markets featuring locally-foraged fungus?
“We do have a concern that more and more wild collected mushrooms are showing up in farmers’ markets and things like that. That’s relatively uncontrolled at the moment,” Mueller said.
The Illinois Department of Public Health does take steps to prohibit the sale or distribution of what it calls “wild-type mushrooms” by ensuing that they meet safety criteria. Wild mushrooms sold to the public must be identified as members of the Morchella Species, and they must be uncooked or cut, as well as free from any type of spoilage. They must also be accompanied with a consumer advisory statement informing purchasers that the mushrooms have been picked in the wild and have not been approved as safe by an expert.
Mueller and Fischbein said that wild mushroom enthusiasts should refrain from eating fungi without first consulting an expert. But with the help of educational sessions and excursions, they can safely enjoy their bounty.
“In the Chicago area, there are mushroom clubs you can join to get more information – like mycological associations, lectures [and] field trips to learn about edible-mushroom classes, “Mueller said. ” There is no super easy way to do it,” he added “You just have to know what the mushrooms are.”