Which mushrooms are mildly toxic when fresh?

Morels are known to be mildly toxic when they are fresh due to the presence of a toxin called gyromitrin. While properly cooking morels destroys this toxin, consuming them raw can lead to symptoms of poisoning.

In contrast, the other types of mushrooms listed, such as portobellos, button mushrooms, and shiitake, do not exhibit this level of toxin when fresh. Portobellos and button mushrooms are essentially the same species, and both are widely consumed without any issues when cooked. Shiitake mushrooms are also safe when cooked and are popular in various dishes.

Therefore, the unique characteristic of morels being mildly toxic when fresh distinguishes them from the other options. Understanding the nature of morels highlights the importance of proper preparation and cooking in mushroom consumption.