Here is an easy way to remove bathroom mold from the tile floors:
Combine 1/3 part bleach with 2/3 part water in a spray bottle and spray liberally on the tile floor, wherever you see black little dots of mold. Let sit for half an hour or so, making sure to ventilate the area.
Sprinkle a 1:1 combination of salt and baking soda on the areas that you bleached. Scrub well and rinse.