Industrial Dyes with Potential for Genotoxicity/Carcinogenicity

By: Ingrid Hayenga, Senior Chemist R&D Europe, AnalytiX Volume 9 Article 1

New standards for the reliable analysis of these illicit compounds

In Analytix 4 (2008), we introduced a new group of standards, Sudan dyes, which are banned as food additives worldwide1 but are sometimes still used illicitly to enhance and maintain the colour of food, especially chili and chili-derived products.

Since May 2005, industrial and other kinds of dyes have also been found in food, despite the fact that these compounds are not authorised as food colours by the European Parliament and Council Directive 94/36/EC on colours for use in foodstuff. As such, Sigma-Aldrich offers a wide variety of analytical standards useful for the testing of foodstuffs for these dyes.

The European Commission asked the European Food Safety Authority (EFSA) to carry out a review of toxicological data available for dyes similar to Para Red, Sudan dyes, Rhodamine B, etc. to determine the extent of the problem. The EFSA split the examined dyes into two groups. The first part, known as Annex 1, included Sudan I to IV, Para Red, Rhodamine B and Orange II dyes. Annex 2, the second and wider part, was to identify and compile a list of other potentially genotoxic/carcinogenic dyes considerated harmful because of their structureactivity relationships, based on the Monographs of the International Agency for Research on Cancer (IARC), publications of the U.S. National Toxicology Program (NTP) and other relevant sources. These dyes belong to the group of azo, triphenylmethane or anthraquinone dyes.


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  1. “Opinion of the Scientific Panel on Food Additives, Flavourings, Processing Aids and Materials in Contact with Food on a request from the Commission to review the toxicology of a number of dyes illegally present in food in the EU” The EFSA Journal (2005) 263, 1-71.