FD & C Red No 3
FD&C RED No. 3
Erythrosine, also known as Red No. 3, is an organoiodine compound, specifically a derivative of fluorone. It is cherry-pink synthetic, primarily used for food coloring. It is the disodium salt of 2,4,5,7-tetraiodofluorescein. Its maximum absorbance is at 530 nm in an aqueous solution, and it is subject to photodegradation.
It is used as a food coloring, in printing inks, as a biological stain, a dental plaque disclosing agent and a radiopaque medium. It was used as a sensitizer for orthochromatic photographic films. Erythrosine is commonly used in sweets such as some candies and popsicles, and even more widely used in cake-decorating gels. It is also used to color pistachio shells. As a food additive, it has the E number E127.
While commonly used in many countries of the world, erythrosine is less commonly used in the United States (the second least used after Fast Green FCF) because Allura Red AC (Red #40) is generally used instead. However, Allura Red AC is banned in many European countries solely because it is an azo dye, despite scientific consensus of Red 40 having fewer known health risks.