Citrus Red No. 2 is a synthetic dye the FDA permits for one purpose only: coloring the skins of whole fresh oranges that are already ripe. Federal rules cap it at 2.0 parts per million of the fruit’s weight and require stores to tell you when oranges have been treated. Most of the world, including the entire European Union, prohibits the dye based on animal studies linking it to cancer, and international food-safety authorities have withdrawn their approval of it.1World Health Organization JECFA Database. Citrus Red No. 2
What the Dye Is and Why It’s on Oranges
Citrus Red No. 2 is an azo dye, a synthetic organic compound whose principal component is 1-(2,5-dimethoxyphenylazo)-2-naphthol, molecular formula C₁₈H₁₆N₂O₃.2PubChem. C.I. Solvent Red 80 It doesn’t dissolve in water but does dissolve in organic solvents, which is why it binds to the waxy surface of an orange peel instead of soaking through to the fruit.
The reason for using it is cosmetic. Oranges grown in warm climates often stay green or pale on the outside even when the fruit inside is fully ripe and sweet, because the chlorophyll in the peel needs cool nighttime temperatures to break down. The dye gives those oranges the deep orange color shoppers expect.
Where You’ll Run Into It
Packinghouses apply Citrus Red No. 2 through a process called color-adding, running oranges through an emulsion or wax coating that carries a small concentration of the dye. It’s an exterior treatment only, and the rules are written to keep it on the rind.3U.S. Food and Drug Administration. Color Additives Questions and Answers for Consumers
Two boundaries limit where you’ll find it. First, only whole oranges that have already met the maturity standards of the state where they were grown may be dyed. Those standards use sugar-to-acid ratios, so a dyed orange has to be a ripe orange to begin with. Second, oranges destined for juice or other processed products cannot be treated.4eCFR. 21 CFR 74.302 – Citrus Red No. 2
How You’ll Know an Orange Has Been Dyed
For oranges sold loose at retail, the FDA doesn’t require a sticker on each fruit. Instead, the store must either keep the bulk container’s label visible to shoppers or post a sign, counter card, or similar notice prominently stating that the oranges are artificially colored.5Food and Drug Administration. CPG Sec 550.625 Oranges – Artificial Coloring If you don’t see a notice, the fruit shouldn’t have been dyed.
The Safety Picture
The International Agency for Research on Cancer classifies Citrus Red No. 2 as Group 2B, “possibly carcinogenic to humans,” a designation established in IARC Monograph Supplement 7 in 1987 and drawn primarily from animal evidence.6International Agency for Research on Cancer. Agents Classified by the IARC Monographs7International Programme on Chemical Safety (IPCS) INCHEM. IARC Summary and Evaluation for Citrus Red No. 2 Rodent studies have shown urinary bladder tumors.8IPCS INCHEM. Summary of Evaluations Performed by the Joint FAO/WHO Expert Committee on Food Additives – Citrus Red No. 2
The Joint FAO/WHO Expert Committee on Food Additives set the acceptable daily intake to “not to be used” and withdrew its specifications for the dye in 1990, concluding the toxicological data were inadequate to establish any safe consumption level.1World Health Organization JECFA Database. Citrus Red No. 2 The European Union does not authorize Citrus Red No. 2. Canada is the outlier that mirrors the U.S. approach, permitting the dye on the skins of whole oranges at the same 2.0 ppm limit.9Health Canada. List of Permitted Food Colours
What This Means When You’re Eating an Orange
Actual exposure is small by design. The dye sits on the outside of a peel most people throw away, and the 2.0 ppm cap keeps concentrations low even on that surface.4eCFR. 21 CFR 74.302 – Citrus Red No. 2 The main way any of it reaches you is transfer from the peel to your hands while you’re peeling the fruit, and then to your mouth. Washing your hands afterward, or rinsing the orange before you peel it, cuts that already-small exposure.
Zest is the situation to pay attention to. If you grate orange peel into a recipe, you’re eating the treated surface directly, so it’s worth choosing oranges labeled as untreated, or organic fruit, when the peel itself is the ingredient. Fruit sold for juicing or processing can’t be dyed to begin with, so juice you buy at the store isn’t a route of exposure.