Mushrooms: Kosher Status, Blessing.
Mushrooms are fungi. They are not the seed-bearing plants the Torah allows man to eat. If so, how can they be kosher?
The Aish Rabbi Replies
You are right that mushrooms do not grow from the ground in the same manner as plants. The Talmud recognizes that although they often grow on the ground, they do not receive their nourishment from the ground (Brachot 40b). Unlike plants, fungi do not produce their own carbon, but draw it from other organisms, usually decomposing plants.
Even so, there is no reason they should not be kosher. The Torah specifies which foods we may not eat – which includes most of the animal kingdom – almost all insects, most animals, some birds, and some types of fish. (See Leviticus 11 and Deuteronomy 14.) But anything not forbidden by the Torah we are permitted to eat.
In your question, you were presumably referring to Genesis 1:29 in which Adam and Eve were permitted to eat all seed-bearing plants and trees (other than the Tree of Knowledge). It’s not clear altogether if this would exclude mushrooms which do produce spores. But regardless, the laws we follow today are the ones God gave to Moses at Sinai, not what He earlier told Adam or Noah. And the Torah states clearly what is forbidden.
(There are also opinions in the Midrash that had Adam not sinned, there would have been no death in the world at all – not only of man but also of animals. Perhaps when God first instructed Adam in what he may eat, nothing – not even plants – would have ever died and decomposed, and so, there would have been no place for mushrooms in the Garden. This is perhaps why the Torah had no need to permit them to Adam.)
In practical law, although mushrooms in essence are always kosher, there may be kashrut concerns which arise in their processing. Mushrooms which are sold fresh, or dried or frozen without any questionable ingredients, are fine. But canned mushrooms require kosher certification, as sometimes non-kosher ingredients are used in the canning process, or the mushrooms may be processed on the same equipment as non-kosher food. It’s also important to check that mushrooms are not infested with bugs.
In terms of the blessing, since mushrooms do not actually grow from the ground, the blessing said on most plant foods – “Blessed are you… the Creator of the fruit of the earth” is not recited. Rather, we say the same blessing said on meat and other non-plant-based foods: “That all came to being from His word” (“she’hakol ni’hi’ye bidvaro”).
(Sources: Talmud Brachot 40b, Shulchan Aruch O.C. 204:1, Y.D. 84:6.)