Most people think there's a 'special way' to care for those beautiful granite countertops. Well, yes and no. Fact is, the simpler the better. Granite is natural stone and really doesn't appreciate being abused by harsh cleansers and disinfectants. All you need is warm water with a few drops of mild dishwashing liquid and a nubby washcloth. For a little more scrubbing power use a sponge with a scrubbing side, but never use anything more aggressive than that. Rinse the cloth out with fresh water and wipe to remove any detergent and bring out the shine of the surface.
For more details and advice on disinfecting, check out this article.