E131
Patent Blue V

A dark bluish-violet synthetic coal tar dye.

Not widely used but can be found in Scotch eggs and is used diagnostically to colour lymph vessels.

Best avoided by people with allergy reactions as it can cause skin sensitivity, a rash similar to nettle rash, itching, nausea, low blood pressure, tremors and breathing problems.

It is one of the colours that the Hyperactive Children's Support Group recommends be eliminated from the diet of children.

E132
Indigo carmine, Indigotine, FD&C Blue 2

A blue synthetic coal tar dye, normally produced by a synthesis of indoxyl by fusion of sodium phenylglycinate in a mixture of caustic soda and sodamide.

This process was introduced following the discovery of the chemical structure of indigo by the Prussian research chemist J F W Adolf von Baeyer in 1883 and was in regular use by 1890. Very little natural indigo from either Isatis tinctoria or Indigofera has been produced commercially since the turn of the century.

Can be found in blancmange, biscuits and sweets. It is also used diagnostically to check for coloured urine in kidney function tests.

Best avoided by people with allergy reactions as it can cause skin sensitivity, a rash similar to nettle rash, itching, nausea, high blood pressure and breathing problems.

It is one of the colours that the Hyperactive Children's Support Group recommends be eliminated from the diet of children.

Prohibited in Norway.

E133
Brilliant Blue FCF, FD&C Blue 1

A blue synthetic coal tar dye often used in conjunction with E102, Tartrazine, to produce various shades of green.

Can be found in tinned processed peas.

It is one of the colours that the Hyperactive Children's Support Group recommends be eliminated from the diet of children.

Prohibited in Argentina, Bulgaria, Czech Republic, France, Hungary, Italy, Mauritius, Morocco, Poland, Portugal, Trinidad and Turkey.

E140
Chlorophylls and Chlorophyllins: (i) Chlorophylls (ii) Chlorophyllins

A fairly unstable olive to dark green dye, which tends to fade easily (see E141). Naturally occuring in the cells of plant leaves and responsible for photosynthesis. Not easy to obtain in a pure form and commercially available chloroyphyll usually contains other plant material impurities.

The usual sources are nettles, spinach and grass with the chloroyphyll being extracted using acetone, ethanol, light petroleum, methylethylketone and diachloromethane. Lutein, E161b, may be extracted at the same time.

Can be found in chewing gum, fats and oils, ice cream, soaps, soups, sweets and, obviously, green vegetables.

Has no maximum recommended daily intake and is not subject to any prohibitions.