How long does dried black fungus last?!

Helen-It is dried. Therefore it is preserved. I does not have preservatives. All you do is keep it stored in an airtight container (a glass jar is best) but plastic is fine too and it will keep almost indefinitely like tea leaves.

Probably no preservatives in the black fungus.
Reason... it's dried so there's no moisture to support bacteria, mold and other microorganisms.
The only thing you really have to worry about is bugs getting into the package, but if you store in a container with a tight fitting lid, the stuff should last indefinitely.

The great thing about dried fungus is that, if properly stored (air-tight and away from light) they will last indefinitely until they are hydrated