Food additives are non-nutritional substances added to food products. They are used for technical purposes, such as the emulsification of fats, the binding of water, or to protect and preserve products from microbial deterioration.

Some food additives are necessary to ensure that products are safe to eat. There is a number of different categories of food additives, each according to the function of the additives, and a food additive numbering scheme has been established to order the additives in the different categories. The numbering scheme was first established within the European Union where food additives are given an ‘E number’ or ‘Europe number’ and all food additives used in the European Union have to be approved for food safety by the European Food Safety Authority.

The numbering system adopted by the European Union is now used by countries in many parts of the world, but without the letter E. The system has also been adopted by the Codex Alimentarius Commission, a body established by the Food and Agriculture Organisation (FAO) of the United Nations. In some instances an additive which possesses an E-number for use within the European Union may be used in another part of the world, eg. Australia, without the E and just the number. However, there are additives approved for use in countries which are not part of the European Union which have allocated classification numbers to additives which are not approved for use in the EU. Different countries may take different positions about which additives are or are not approved for use.