Someone emailed and asked:
Does God permit us to eat mushrooms? Since yeast is a fungus, even as mushrooms are, why then are we allowed to eat bread, drink wine, etc.?
I cover this in several of my books.
It is an inference and not an outright command. “Every green herb bearing seed within itself have I given thee for meat.”
Mushrooms do not fall in this category (at least, not according to modern scientific understanding). This does not mean that God forbade things that don’t fall in this category, for had He forbade them He would have said, “Thou shalt not”.
However, you miss the point. Beer / wine / spirits are not yeast and bread is not yeast. Yeast feeds off sugar / carbohydrates and the by-product is CO2 (carbon dioxide) and alcohol, and B-vitamins. There is little to no yeast in finished wine, beer, spirits; likewise with leavened bread. The majority is destroyed through baking. There may be trace amounts that are only noticable by people with extreme candida albicans (systemic yeast overgrowth, which causes a host of illnessess, possibly 85% of illnesses that doctors misdiagnose).
However, if a person ate a tablespoon or bowl of yeast, he would get very sick or even die, depending on how much he ate. Yeast is in the air. It is not intended to be a food group or a meal in and of itself.
The same logic can be applied to things like lye, potassium nitrate that are used to prepare or preserve some foods, but would never be consumed by themselves, or even used as seasoning.
Even as with bread and wine, so it is with cheese (and even other fermented foods like Miso, natto, tempeh, tofu, etc.). While various different molds ferment the cheese (or soy), one does not eat the yeasts, fungi, or molds in their pre-fermented state all by themselves, or even add them to food as a condiment. Their use as food is not a seasoning or ingredient, but a fermenting agent.
It is not “adding to” the Law of God or deciding which fungi is eatable or not. God commanded at Passover and Unleavened bread to eat unleavened bread. If we were not allowed to eat yeast-risen bread, then it would be senseless to have days of Unleavened Bread as something special. Some strains of fungi may be appropriate in medicine (penicillin), and also in fermentation process, but since fungi are not green herbs and do not have seed within themselves, but reproduce by spores, although God did not specifically forbid them, Scripture also tells us that whatsoever is not of faith is sin. Since many mushrooms are poisonous, and since yeast itself causes a plethora of illness (candida albicans), then it seems unlikely that fungi are intended to be a food group. Scripture does not say “Nay”. However, neither does it say “Yea” nor give us any form of application for fungi other than in the fermentation process. But we do know that Christ ate leavened bread and also drank wine.
God does not say that mushrooms are forbidden, but neither does He suggest that we eat them. I don’t eat them. He does not say that they are unclean, so I will pick them out or off a food and eat it; but I would never do that with anything that was unclean (whether pig meat, a garden slug, or dog poop); that which is unclean defiles that which it touches.
Some mushrooms or symbiotic fungi colonies, such as chaga, lion’s mane, kombuchu, maitake, reishi, kefir, etc. are reported to have many health benefits and even be superfoods. In these cases, it seems that the Biblical admonition, “let each be persuaded in his own mind” should apply—not ignorantly (for whatsoever is not of faith is sin, and faith is not some nebulous ether, but is based on facts), but via informed research.