The US Food and Drug Administration (FDA) has issued a guideline about how to check if decorative glitter is edible.
According to the FDA, many decorative glitters and dust are sold under names such as luster dust, disco dust, twinkle dust, sparkle dust, highlighter, shimmer powder, pearl dust and petal dust. Of these, some are edible and produced specifically for use on foods and may be safely eaten, however, there are those that cannot be consumed.
The simplest way you can determine whether the glitter is edible or not is to turn the packaging over and check for the list of ingredients, as companies are required by law to include a list of ingredients. If this is missing, the product isn’t edible.
The FDA also noted common listed ingredients would include sugar, acacia, maltodextrin, cornstarch, and colour additives approved for food use, and the packaging would also state “edible” on the label.
If the label says non-toxic or for decorative purposes, then the product should not be used on foods.