Why is the mold on blue cheese edible while other molds are not?

Blue cheese has added mold of the genus Penicillium, most often Penicillium Roqueforti and Penicillium Glaucum, that is related to the mold that makes penicillin. Penicillium actually helps prevent the growth of harmful molds that cheeses get, like Clostridium and Staphylococcus.

Oh, also, I should mention – while the mold of blue cheese is related to the mold of antibiotics, should you have a yeast infection or something? You should not try to fix that by eating $15 worth of Roquefort; that’s really an ineffective way to cure pretty much anything other than a hankering for really yummy food.

You can eat other molds on cheese, but the flavor may not be as pleasant as the blue mold. I don’t care for the white mold, so I carefully cut it off with a thin strip of cheese and serve it to my husband. He likes it, mold and all, and it doesn’t seem to do him any harm.

Some molds produce toxins—specifically, mycotoxins—as a by-product of their metabolism. It isn’t actually the mold itself that’s toxic; the toxin can diffuse through the food, and persist even if the mold is removed.

The mold in blue cheese can produce mycotoxins, too, but rarely in cheese. Grown on other substances, and under certain conditions, though, it can be mildly toxic.

Think of it like edible mushrooms and poisonous ones.

@Aethelflaed penicillin kills bacteria not yeast. In fact the overkill of good bacteria promotes yeast growth in certain parts of the body.