Chronic toxicity of two food colors, Brilliant Blue FCF and Indigotine

Brilliant Blue FCF (FD & C Blue No. 1) and Indigotine (FD & C Blue No. 2) were fed to groups of 24 Osborne-Mendel rats for two years at dietary levels of 0.5, 1.0, 2.0, and 5.0%. Growth inhibition occurred in the male animals fed Indigotine at the 2.0 and 5.0% levels. No effect was observed on survival, hematology, or organ weights. No significant pathologic changes were observed in animals fed either color. Five beagle dogs received a dietary level of 2.0%, and three dogs a level of 1.0% of Brilliant Blue FCF for one year. One dog died after 17 days on the 2% dietary level and another died after 46 weeks on the 1% level. Indigotine was fed to beagle dogs for periods up to two years at dietary levels of 1.0 and 2.0%. Four of the six dogs at the 2.0% level died during the two years, and one of the four at the 1.0% level was sacrificed in a moribund condition. All the deaths were attributed to intercurrent virus infections. No clinical signs, gross lesions, or microscopic pathology were attributed to intercurrent virus infections. No clinical signs, gross lesions, or microscopic pathology were attributed to ingestion of Brilliant Blue FCF or Indigotine; however, because of deaths from intercurrent virus infections a no-effect level has not been established for Indigotine. Subcutaneous injections of 30 mg of Brilliant Blue FCF or 20 mg of Indigotine into rats weekly for two years produced fibrosarcomas at the site of injection. Other than acute convulsive deaths of some of the test mice immediately after injection, no deleterious effects attributable to the weekly subcutaneous injection of 2.5 mg of Indigotine were observed over a two-year period.