Sometimes the cure is near as bad as the problem...
My first inclination would be to order a new gasket
but you will still have to be in & around mold.
Inspect the GASKET and make sure it is
pliable & completely intact. Spray NOTHING
directly on the gasket.
Pardon my California spelling...
but there are
some anti-fungal sprays
(in building supplies)... after you have the goggles, dust mask & gloves... get some disposable RAGS and protect EVERYTHING near-by... It is every bit as FRIENDLY (not) as industrial strength carburetor cleaner
(face skin tightens up (not good)).
Have a trash container close by:
Sparingly ... and repeatedly...
spray it on a RAG and apply it around your
gasket and mating surface... wipe it clean.
Rinse the gasket with clean water (on another rag).
Apply food grade silicone to a clean rag and wipe down the gasket and the mating surface.
Do NOT spray silicone directly on the gasket.
Dispose of those rags like they are radio-active
(well... ok... maybe just seriously obnoxious).
Sorry to hear of your water/washer issues...
Hope this helps
Carnac the Magnificent