The investigation found that undercooked or raw morels were the likely culprit, and it led the FDA to issue its first guidelines on preparing morels.
A food poisoning outbreak that killed two people and sickened 51 has highlighted just how little is known about morel mushrooms and the risks in preparing the popular and expensive delicacy.
The FDA conducted an investigation into morel mushrooms after the severe illness outbreak linked to Dave’s Sushi in Bozeman, Montana, in late March and April. The investigation found that undercooked or raw morels were the likely culprit, and it led the agency to issue its first guidelines on preparing morels.
“The toxins in morel mushrooms that may cause illness are not fully understood; however, using proper preparation procedures, such as cooking, can help to reduce toxin levels,” according to the FDA guidance.
Even then, a risk remains, according to the FDA: “Properly preparing and cooking morel mushrooms can reduce risk of illness, however there is no guarantee of safety even if cooking steps are taken prior to consumption.”
People think of mushrooms like vegetables and most wouldn't suspect that it's often more important for mushrooms to be fully cooked than it is for meat.
People eat rare burgers all the time and only rarely get sick, morels are actually poisonous when undercooked so you're guaranteed to get sick if you eat enough of them.
My brother in law used to eat baby potatoes raw as a snack. Pack them in his lunch for work. Never bothered him but he is an interesting dude. With a stomach of steel apparently.
Those are both the same mushroom, Agaricus Bisporus which is mildly toxic and carcinogenic when eaten raw. You probably won't get an upset stomach unless you eat a lot of them but it's really not worth the risk just to ruin a perfectly good salad with nasty raw mushrooms.