Orcein
A natural lichen-derived purple dye once used to colour food. No longer permitted as a food additive in the UK or EU.
E182 should not appear on any UK or EU food label. If you see it listed, the product may be in breach of food law. Report it to the Food Standards Agency.
What is it?
Orcein, also called orchil or archil, is a red-to-purple dye extracted from several lichen species, principally Roccella tinctoria. It is a complex mixture of phenoxazone derivatives produced when orcinol from the lichen reacts with ammonia and oxygen. Its colour shifts from red in acidic conditions to blue-purple in alkaline conditions. Historically also known by the E number E121 before its food use was discontinued.
What does it do?
As a colourant it imparts shades from red through purple depending on the pH of the food matrix. It was used purely for appearance, providing a visual cue of ripeness or flavour associations. Today it is used outside food as a laboratory stain in histology and microscopy to highlight elastic fibres, chromosomes and certain antigens in tissue samples.
Where you will see it
Orcein is not permitted in UK or EU food products. Historically it appeared in some confectionery and drinks before the European ban that took effect in the mid-1970s. In legitimate current products it should be absent from ingredient lists entirely. The names to recognise on a label are orcein, orchil, archil, or E182.
What the science says
Regulatory withdrawal after toxicological review
When the EU updated its food colour rules in Directive 94/36/EC, orchil was among the substances removed from the permitted list. The Scientific Committee on Food concluded, based on its evaluation of available toxicological data, that the evidence was insufficient to maintain the colour's authorisation. The specific toxicological concerns that prompted withdrawal have not been published in detail in the public domain. Because the removal was driven by a data gap rather than a demonstrated hazard, no IARC classification or specific harm endpoint was assigned.
Orchil was deleted from the EU positive list of permitted food colours in Directive 94/36/EC, alongside seven synthetic colours, on the basis of the Scientific Committee on Food's evaluation of toxicological data.
Orcein is not listed in Annex II of the UK assimilated version of EU Regulation 1333/2008, which sets out the positive list of permitted food additives. The UK FSA approved-additives list stops at E180 (Litholrubine BK) for the colour category; E182 does not appear.
Early laboratory research on orcein derivatives and Alzheimer's disease
Researchers at the Max Delbruck Center in Berlin screened natural compounds for potential use against neurodegenerative disease and identified orcein as a candidate. A derivative compound called O4, structurally related to one of the phenoxazone components of orcein, was found in laboratory cell-based assays to accelerate the conversion of small toxic amyloid-beta aggregates into larger, apparently less harmful fibrils. This research is early-stage: it was conducted in cell culture and has not been tested in animals or humans as a therapeutic. It does not change E182's regulatory status as a prohibited food additive.
Orcein and a related phenoxazone derivative O4 promoted conversion of small amyloid-beta oligomers into larger beta-sheet-rich fibrils in laboratory cell-based assays, reducing the toxicity of those oligomers to cultured neurons.
Where it stands with the regulators
Who should be careful
Everyone in the UK and EU is protected from exposure via food because the additive is not legally permitted. Anyone buying food from outside the UK and EU should check for the names orcein, orchil, archil, cudbear, or E182 on the label.
The honest read
The regulatory situation is clear: orcein has not been permitted in UK or EU food since the 1970s and the ban was reaffirmed when EU food colour law was modernised in 1994. The specific toxicological data that led the Scientific Committee on Food to withdraw approval has not been published in a publicly accessible opinion document, so the precise hazard profile for food-level exposure is not on the public record. There is laboratory research exploring orcein derivatives as possible tools in Alzheimer's disease research, but that work involves purified compounds at controlled doses in cell cultures and does not indicate any food-safety benefit. The science on orcein as a food exposure is thin, which is itself part of why it was not retained on the permitted list.
Related additives
Common questions
Is E182 banned in the UK?
Yes. E182 (orcein, also called orchil) is not a permitted food additive in the UK or EU. It was removed from the approved colours list when EU food colour law was updated in 1994, and that position is retained in current UK law following Brexit. It should not appear on any UK food label.
Why was orcein removed from the permitted food colours list?
The EU's Scientific Committee on Food reviewed available toxicological data and concluded there was insufficient evidence to maintain the authorisation. Orchil was among a group of colours deleted when Directive 94/36/EC replaced the original 1962 Directive. The committee's detailed opinion on orchil has not been published in full in the public domain, so the specific concern is not precisely documented.
What foods contain E182?
No UK or EU food products should legally contain E182. Historically, before the ban took effect in the 1970s, orchil appeared in some confectionery and beverages. If you encounter a product in the UK or EU listing orcein, orchil, archil, or E182 as an ingredient, it may be in breach of food additive law.
Is E182 vegan?
The dye is derived from lichens, which are composite organisms made up of fungi and algae rather than animals. By most vegan standards the source material is not animal-derived. However, traditional production methods used urine as an ammonia source during processing. Modern preparations use industrial ammonia. As the additive is not permitted in food in the UK or EU, the question of its vegan status in a food context does not arise in practice.
Sources
- UK Food Standards Agency: Approved additives and E numbers
- European Parliament and Council Directive 94/36/EC on colours for use in foodstuffs
- Regulation (EC) No 1333/2008 on food additives (Annex II positive list)
- NATCOL: Food Colours Legislation - full article (analysis of Directive 94/36/EC deletions)
- Wikipedia: Orcein (chemistry, regulatory status, uses)
- EurekAlert / Max Delbruck Center: A natural dye obtained from lichens may combat Alzheimer's disease (orcein and O4 amyloid research)
- Bieschke J et al., Small-molecule conversion of toxic oligomers to nontoxic beta-sheet-rich amyloid fibrils, Nature Chemical Biology
- OpenFoodFacts: E182 Orcein additive page
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