Finally! The FDA has approved spirulina as a source of blue color in candy and gum. This is a natural alternative to the artificial blue color FD&C Blue #1 that is current used in the US. Spirulina comes from algae that grows on the surface of lakes. It is a high-quality protein, often used as a supplement.
Studies on sprirulina showed no toxic effects for lead, arsenic or mercury. It also showed low probability for allergens.