Patching and Plastering - Mildew and plaster repair

Have mildew inside cabinet of basement bath on interior wall. Don't know for sure but do not suspect leak between walls. Have fan in shower and run dehumidifier in past months. My guess is excess moisture in enclosed area. Would it be benefit to run a small fan inside this cabinet periodically? I've tried the damp rid stuff and it did nothing. Plaster is cracking and crumbling in this area also. Any suggestions on repairing this?

Surfaces affected by mold and mildew should be disinfected with bleach/water solution. Mildew spores are everywhere in the air. When they find a dark, damp, poorly ventilated area they tend to settle in. Running dehumidifier in room will reduce humidity levels. Running bathroom fan for about 30-45 minutes after bathing will help in exhausting humidity from room. Leaving cabinet door open will improve air circulation in cabinet. Running a fan in the room will improve air circulation and expedite the drying of surfaces. Make sure bathroom vent is vented to the outdoors to assure that humidity is being exhausted out of the room.

I am moving this thread from Walls & Ceilings to Plaster & Patching Forum for help with your cracking and crumbling plaster problems.

I think if you nose around here there are plenty of posts about patching the plaster. If the plaster is crumbling you have a moisture problem of some kind. Get that solved first.