If mold or mildew are growing beneath the floor, the conditions are far too damp. First step is to eliminate sources of moisture. Then mix about 3/4 cup of bleach with one gallon of water in a clean garden-style sprayer.
Wearing old clothing and goggles or safety glasses (and a respirator if the conditions make one necessary), spray the framing with this bleach/water mixture.
If you don't wear a respirator, avoid breathing the spray.
Following application, wipe off the mildew with a rag (or scrub with a brush, if necessary).
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