You can use a spray bleach cleaner or make your own, in a spray bottle mix 1 part bleach to 10 parts water(1:10). Let it sit for 10 minutes and wipe away with a paper towel. If the mold is really bad then an abrasive(Borax, baking soda, etc) and a old toothbrush will work.

I have had good luck with Tilex, which contains bleach.

Here is a link that might be useful: Tilex Mildew Root Penetrator and Remover

At work, for really bad mold in the shower house, I soak cotton batten rope (the kind they use at hair salons to keep the hair dye out of your eyes) soaked in a bleach solution and then laid over the moldy areas. Leave it for an hour or so, remove it and then take a scrub brush to remove all residue. Works really quite well.

After you get rid of the mold, seal the grout with a sealer intended for wet areas. It's easy. You brush the liquid on with a small brush along the grout lines and let it dry.

I dip an old toothbrush in a cup of diluted bleach & scrub @ the mold - going over the area several times if necessary, then rinse well. An old dish detergent bottle makes a good squeeze bottle for rinsing.

Spraying bleach (even diluted) can really burn your nose & throat (not to mention your eyes) if you're not careful. We're almost always dealing w/ mold here in humid Florida & I've learned the hard way.

Also be careful of your clothes & any nice bath towels/washcloths when doing that - splattered bleach is very sneaky - & permanent.