If the grout isn't sealed (I've used polycrylic and modgpodge, I like polycrylic better) the grout can stain, it's really porous.
I use F10 to clean things, zoomed makes a product called wipe out! that is similar. vinegar/water is good for small cleaning but probably isn't effecitve against parasites and a wide range of germs. A steam cleaner is also a good optio with not chemical residues. I don't care to use bleach regularly it's pretty nasty.