Brown HT is a reddish brown food dye. It is also known by the names chocolate brown, food brown 3, C.I. 20285, or the E Number 155.
Brown HT is a diazo dye. Diazo refers to a type of chemical compound that has two linked nitrogen atoms (the French word for nitrogen is azote). Azo dyes account for roughly 60 to 70% of all dyes used in the food and textile industries. The reason they are so popular is that azo dyes are cheap to produce and are more stable than most natural food dyes.
It is sometimes referred to as a coal tar dye, but this is a bit misleading. The chemicals may have first been discovered during experiments with coal tar. However, like many organic compounds used in food additives and pharmaceuticals today, Brown HT is produced byproducts of the petroleum industry. This shouldn’t be as scary as it sounds. Once the organic compounds have been extracted, the source isn’t important.
The chemical name is Disodium 4,4-(2,4-dihydroxy-5-hydroxy methyle-1,3-phenylene biazo)di(napthelene-1-sulfonate.)
Brown HT is mostly used as a food dye in the baking industry. The suffix HT is for high temperature, meaning the dye is stable during baking.
Although it is used mainly in chocolate cakes, it might also be found in milk, cheeses, yogurts, and jams.
It is not allowed in Canada2 or the United States3. It is approved in the European Union4, but may be banned in individual countries such as Austria, Belgium, Denmark, France, Germany, Norway, Switzerland, and Sweden.
Brown HT is approved in Australia where it is common in chocolate milk.
Side Effects/Health Issues:
The European Food Safety Authority says that there have been no cases of intolerance or allergies have been reported after oral exposure to Brown HT. However, many other internet sources indicate it may produce allergic reactions in people with asthma or people sensitive to aspirin. This is likely due to the fact that it is related to the azo dyes like Allura Red.
It is currently quite hard to do an internet search for products containing a particular additive. However, the FDA does publish import alerts for items that contain banned substances. In the case of Brown HT, we can see that it was found in biscuits from Fiji and in cake decorating supplies from the UK.