Mushrooms go moldy - what is the white fluff?

White fluff on fresh mushrooms is not mold

White fluff is mycelium

What we commonly refer to as a “fungus” is basically just the fruiting body of the fungus that actually grows underground, the mycelium. This is a widely branched network of white threads that runs through the soil or growing medium and is sometimes noticeable on very ripe fruit bodies. In order to multiply, these release spores from which new mycelium eventually grows. In this respect, your mushrooms, with their white threads running through them, are not bad, just very ripe - which is why a new mushroom mycelium has already formed. If you want, you can use these specimens to grow your own mushrooms or simply wipe the mycelium with a kitchen towel. The mushrooms are definitely still edible.

When is it better to throw away mushrooms?

However, this only applies as long as the mushrooms with the mycelium still look fresh and crisp and give off a pleasantly mushroom-like smell. Under no circumstances should you use them (but instead dispose of them) if you notice the following:

Mushrooms have a strong or unpleasant smell.
Mushrooms don't look fresh anymore, they have a lot of dark spots.
Mushrooms are covered with colored fluff.
Mold on mushrooms are usually black, brown or green.
Mushrooms have rotten or musty spots.

In these cases - only one of the characteristics mentioned has to apply! - the mushrooms must be disposed of, otherwise you risk food poisoning.

Store fresh mushrooms properly

To ensure that fresh mushrooms do not actually go moldy, you should take them (if you have bought them) out of their packaging (usually plastic boxes) and store them in a cool, dry and dark place. The best place for this is the vegetable compartment of the refrigerator, where the mushrooms, wrapped in a dry and clean kitchen towel, will keep for three to four days. However, fresh mushrooms are best processed on the same day, as they spoil very quickly due to their high water and protein content.