<Tr> <Td> </Td> <Td> </Td> </Tr> <P> Allura Red AC is a red azo dye that goes by several names including Allura Red, Food Red 17, C.I. 16035, and FD&C Red 40 . It is used as a food dye and has the E number E129 . </P> <P> The compound is a derivative of naphthalene and a dark red powder . It usually comes as a sodium salt, but can also be used as both calcium and potassium salts . These salts are soluble in water; in solution, its maximum absorbance lies at about 504 nm . Its melting point is above 300 ° C (572 ° F). </P> <P> Allura Red AC is a very popular dye throughout the world . Annual production in 1980 was greater than 2.3 million kilograms . </P>

Where does red dye number 40 come from