Bacterial Azo Reduction: a Metabolic Reaction in Mammals

THE sulphonated water soluble azo dyes are widely used as colourings for foods and pharmaceutical preparations. Because some dyes are carcinogenic and others are known to be toxic, the metabolism and excretion of azo compounds are of considerable interest. Oral ingestion of dyes brings them into contact with the flourishing microbiological population of the gastro-intestinal tract. It is therefore useful to consider what part the gut flora play in the metabolism of azo dyes.