Glow-in-the-dark candy is one great item to serve at your parties. Unfortunately, truly phosphorescent substances, while non-toxic, aren't classified as "food grade" by the U.S. Department of Agriculture. They aren't meant to be used in foods. So, you can't make candy that will glow in the dark on its own, as the USDA hasn't approved any phosphorescent chemicals for use in food. However, there are other methods available for making your candy appear to glow, all of which take advantage of natural chemical processes and physical laws.
Things You'll Need
Rub together two wintergreen mint candies or sugar cubes in a dark room. These candies -- or any candy made with sugar -- will produce small blue sparks when crushed. The effect is the result of a process called Triboluminescence, which is essentially light from the friction of rubbing two special materials together. You can also chew the candy to produce the same effect, but saliva might mute the strength of the light.
Use tonic water in candy recipes instead of tap water. This is a good option for those using black lights. Quinine glows under black lights and will produce a glow-in-the-dark effect. Quinine is bitter and should be used only sparingly or in products that can mask the taste. It's commonly used in alcoholic drinks for this effect. Some people are also allergic to quinine. It's highly recommended that you only use this method if you are certain your guests won't have a reaction.
Serve white or neon-colored candies under black lights. Black lights produce light that isn't visible to the human eye, so a light room appears dark. When these light waves strike objects containing phosphors, the phosphors will produce visible light waves making them appear to glow. Make your own candies using white chocolate and serve them under a black light.
Don't use phosphorescent products in your candy. These products may or may not be toxic, depending on the type of phosphorescent chemical used.