EVERY ONCE IN A WHILE SOMEONE WRITES TO OUR WEBSITE TO ASK ABOUT MUSHROOMS ARE CONSIDERED "CLEAN" FOOD.
Great question and the simple answer is "Yes"- because YHWH gave no prohibition on fungi.
While Scripture is very clear on many issues, it isn't replete with every little detail concerning all aspects of life, and so sometimes we're left to figure things out on our own ... using our knowledge of Scripture and some common sense.
For instance, the scriptures of Genesis regarding food are very general, not intended to be a complete, thorough, and solid reference of do's and don'ts. There are no other mitzvah (instructions/rules) presented in the Bible narrowing down what green plants can be consumed and which can't. In that, we have to use our own brains. So, while YHWH doesn't prohibit the eating of any plants, some plants will hurt or kill us - and therefore, we must choose wisely!
In the story of Elisha's miracle in 2 Kings 4: 39-42, the words of verse 39 translated as "wild squash" (Sterns) or "gourds" (NIV), in Hebrew is "paquot sade" or "fungi of the field". So it seems we have a story in the Bible which gives credence that fungi, which includes mushrooms, are not expressly forbidden.
According to this logic, mushrooms are edible. (As a matter of fact, Chabad.org, insists that mushrooms are kosher.) Some have even argued that manna was a sort of fungi. As a matter of fact, Talmud Bavli, in Shabbat 30b, gives the following opinion about the miraculous fruitfulness of the land of Israel in the Messianic age:
"Come, and I shall show you their equal in this world," [Rabbi Gamaliel] replied. He went forth and showed him morels and truffles.
Another Jewish view of them is that they were not included in the curse of the ground that applied to plants, since they are not vegetation. (Source: The Avnei Nezer - Avraham Borenstein, the first Sochatchover Rebbe, who claimed such in Orach Chayim 111. His claim is that they do not officially come from the ground like plants so they legally were never cursed.)
Additionally, many are highly medicinal, from immuno-modulators to cancer-fighting properties, and some (lion's mane and psilocybin types) exhibit distinct neuroplasticity (the ability for the brain to make new neural connections), and thus are being used for patients with Alzheimer's and similar dementia-like issues.
As further evidence in our “mushroom debate,” we must discuss the yeast cell, which are fungi, and they are critical to making chametz. Yeast cells are not prohibited by YHWH either! We'd be in big trouble if fungi were prohibited as we breathe yeast cells constantly. In most cases, what yeast we consume is already dead (in both bread and wine), but we do ingest live yeast cells just by breathing. These are promptly killed by our immune systems.
Regardless, for those who consider themselves to be mushroom foragers, it would be wise to make sure you only consume culinary mushrooms from reputable sources, or educate yourself extensively before trying anything you find in the wild, as some will give gastrointestinal distress that would be unpleasant, and a few others can actually shut down vital organs, and so must be avoided at all costs…
Having said all the above, the eating of mushrooms is basically a decision each individual must make on their own.
(NOTE: My gratitude to author, scholar and Amazon Associate, Jeremy Chance Springfield for his learned input to this article! Please check out his website!)