Indigotine (Indigo Carmine)

Indigotine, sold as Indigo Carmine, is a synthetic blue dye derived from indigo. In food it is used to produce blue and green hues in confectionery, beverages, ice cream, and some savoury products. Unlike natural indigo, the food-grade version is a petroleum-derived sulfonated salt that dissolves readily in water.

JECFA evaluated indigotine in 1966 and established an acceptable daily intake of 5 mg per kilogram of body weight per day. For a 70 kg adult this corresponds to a daily limit of 350 mg — a threshold rarely approached through normal dietary exposure, as the quantities used in food are very small. No EFSA-specific ADI data is available in our current record.

Indigotine is one of the less contentious synthetic food dyes: it does not carry the EU mandatory warning label required for the six Southampton azo dyes. It is approved in the EU (E132), the United States (FD&C Blue No. 2), and most other major markets. Sensitive individuals may prefer to moderate intake, but current evidence does not indicate a safety concern at typical exposure levels.