People often choose granite counter tops for their classic looks and durability. Most, however, don't realize that--although physically durable--granite is actually very porous and needs regular thorough cleaning to keep it from staining and darkening over time. Food coloring is one of the most noticeable stains on granite. However, if you take quick action, it does not need to be a permanent blemish.
Quickly blot (do not rub) any excess dye from the granite. Work from the outside of the spot in to keep the stain from spreading. The faster you begin treating the stain, the more chance you have of getting rid of it.
Mix 2 cups of warm water with 2-3 teaspoons of mild detergent. Mix well
Apply detergent solution to the spot with a clean cloth or an old toothbrush and rub gently.
Rinse the area with clean, warm water and dry thoroughly.
Repeat the process as often as needed until all the color is removed from the granite.
If some final, stubborn pigment remains you may wet a cotton ball with bleach or hydrogen peroxide (for light colored granite only) and gently rub the area. If your granite is a dark color, use acetone or lacquer thinner on a cotton ball and apply.