Bathroom mildew is a common shower stall guest. Invited by dark corners, poor ventilation and humid conditions of many shower stalls, mildew makes its presence known with a characteristic smell and discoloration of tiling, walls and other surfaces.
Here's how to make the fungi feel unwelcome: using a spray bottle, concoct a 50/50 solution of hydrogen peroxide and water and apply liberally onto all hard, non-porous surfaces. Let stand and repeat after 2-3 hours. The peroxide is a safe alternative to bleach, yet it's an effective inhibitor of mildew growth. More information about how to prevent or remove mildew here.