Regulatory gap: an E number without authorisation
The E-number system assigns codes to substances under review or once used historically, but authorisation requires a positive safety assessment. E166 was assigned an index number in the mid-twentieth century but has never been included in the EU or UK list of permitted food colours. EU Regulation 1333/2008 Annex II lists colours from E100 to E180 but contains no E164 through E169 entries, including E166. The UK Food Standards Agency approved-additives list likewise contains no E166 entry. An absence from the permitted list means use in food is unlawful in the UK and EU.
E166 does not appear in Annex II of EU Regulation 1333/2008 or in the UK FSA approved-additives list. The colour sequence in that legislation jumps from E163 (anthocyanins) to E170 (calcium carbonate), with no entries in between.
RegulatoryUK Food Standards Agency, Approved Additives and E Numbers; EU Regulation 1333/2008 Annex II (as retained in UK law)
Source plant under international conservation controls
Pterocarpus santalinus (red sandalwood, red sanders) is listed on Appendix II of CITES, which regulates international trade in logs, wood chips, powder and extracts of the species. The IUCN Red List has assessed it as Near Threatened, with earlier assessments classifying it as Endangered due to overexploitation and illegal harvest. Export from India has been restricted by national law since 1996. These trade controls make commercial sourcing for food use effectively impractical, alongside the lack of authorisation.
Pterocarpus santalinus is listed under CITES Appendix II, regulating international trade in logs, wood chips, powder and extracts.
1995RegulatoryCITES, PC17 Doc. 8.4; IUCN Red List assessment of Pterocarpus santalinus
India banned export of red sandalwood under the EXIM Policy and CITES legislation from 1996, with limited exceptions for value-added goods in 1997-2007.
RegulatoryIUCN Red List, Pterocarpus santalinus species assessment
No EFSA or UK safety evaluation for food use
No formal safety evaluation by EFSA or its predecessor the UK Advisory Committee on Novel Foods and Processes has been published for santalin or sandalwood extract as a food colourant. The Joint FAO/WHO Expert Committee on Food Additives (JECFA) evaluated alpha-santalol, the main constituent of white sandalwood oil (a different species, Santalum album), used as a flavouring, and found no safety concern at flavouring levels. That assessment does not extend to santalin pigments from Pterocarpus santalinus used as a food colour.
JECFA evaluated alpha-santalol from Santalum album as a flavouring and found no safety concern at typical food use levels, but this assessment covers white sandalwood oil as a flavour, not red sandalwood pigment as a food colour.
2008Regulatory reviewJECFA, evaluation cited in: Opdyke DL, Safety assessment of sandalwood oil (Santalum album L.), Food and Chemical Toxicology
Santalol: contact allergen in cosmetic use
The EU Scientific Committee on Consumer Safety (SCCS) has classified Australian sandalwood oil as an established contact allergen in humans, based on the santalol content. This assessment relates to skin contact in cosmetics, not to food ingestion of santalin pigments from Pterocarpus santalinus. The two species and their active compounds are distinct. No food-relevant allergenicity data for santalin specifically has been identified in the scientific literature.
The SCCS classified Australian sandalwood oil (Santalum spicatum) as an established contact allergen in humans, based on its santalol content, with positive patch-test incidences of 0.007-1.53% when santalol was tested at up to 10% concentration.
2011Regulatory reviewSCCS, Opinion SCCS/1459/11; Australian Industrial Chemicals Introduction Scheme, Human Health Tier II Assessment: Essential oils, Australian sandalwood
