Patent blue V
Synthetic blue; rare allergic reactions.
- Acceptable daily intake
- 5 mg/kg body weight/day (EFSA)
- Vegan
- Yes
- Vegetarian
- Yes
What it is
Patent Blue V is a synthetic triarylmethane dye — not an azo dye — giving a deep blue-violet.
How it is used in food
Used for synthetic blue coloration.
Commonly found in- Confectionery
- Ice cream
- Liqueurs
- Decorative icing
Health and safety
Can cause rare allergic reactions.
Its rare allergy potential was first documented during medical use.
Regulatory status
| Region | Status | Notes |
|---|---|---|
| Australia & New Zealand FSANZ |
Permitted | Permitted under the FSANZ Food Standards Code. |
| European Union EFSA / European Commission |
Permitted | Authorised for food use under EU regulations (Annex II). |
| United States FDA (Food and Drug Administration) |
Permitted | Authorised for food use by the FDA (often GRAS for standard additives). |
Identification on labels
- E-number
- E131
- Colour index
- CI 42051
Worth knowing
Also used medically to mark lymph nodes during surgery.
Conclusion
There is a minor reason to watch out for Patent Blue V if you have sensitive skin or a history of allergies. While this synthetic triarylmethane dye is generally well tolerated within EFSA's acceptable daily intake of 5 mg per kg of body weight, it can cause rare allergic reactions first noted in medical settings. For most shoppers, it poses little issue in items like confectionery or ice cream.
References
- EFSA evaluation of E131 — EFSA
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Open the appEntry last reviewed 2026-07-28.
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