Black lights that are available to the average person aren't intense enough to kill bacteria, just maybe annoy them...

Bleach is good though.

After you bleach, paint your cellar walls and floor with an oil-based fungicidal paint meant for basements or wet places. I used KILZ and it was fine. Apply it with a small push broom!

Then keep a dehumidifier going.

Voila, no more musty nastiness.