Is this mold in my furnace humidifer?

I recently purchased a home and noticed this inside my furnace's humidifier:

The home has been vacant for at least 6 months, and I hope that this is only due to it sitting unused for so long.

It is very dry and I could wipe it away like it was dust, but didn't want to disturb it anymore in case it was black mold.

If I clean the interior with bleach based cleaner, is that sufficient enough for it to be safe?

If these pictures aren't clear enough I can try to take better ones.

Thank You