Food additives are substances added to food to preserve it, or to improve its flavour and appearance. Some additives have been used for centuries; for example, when preserving food by pickling (with vinegar), salting, as with bacon, or using sulphur dioxide as is common in wine. However, with the advent of processed foods in the second half of the 20th century, many more additives have begun to be used, of both natural and artificial origin.
To regulate these additives, and inform consumers, each additive is assigned a unique number. Initially these were the "E numbers" used in Europe for all approved additives. However, the numbering scheme has been adopted and extended by the Codex Alimentarius Committee to internationally identify all additives, regardless of whether they are approved for use.
E numbers are all written with an "E" in front, but other countries use only the number whether or not the additive is approved in Europe or not. For example, acetic acid is additive 260, so it is written as E260 on products sold in Europe. Additive 103, alkanet, is not approved for use in Europe and so does not have an E number, although it is approved for use in Australia and New Zealand.
See the list of food additives for a complete list of all of the numbers.
Food additives can be divided into several different groups, although there is some overlap between them.
;Acids: Food acids, especially vinegar and citric acid, are added to make the flavour of foods "sharper", and also act as preservatives and antioxidants. ;Acidity regulators: Acidity regulators are used to change or otherwise control the acidity and alkalinity of foods. ;Anticaking agents: Anticaking agents keep powders such as milk powder flowing freely, rather then sticking together in lumps. ;Antifoaming agents: Antifoaming agents reduce or prevent foaming in foods. ;Antioxidants: Antioxidants such as vitamin C act as preservatives by inhibiting the effects of oxygen on food, and are generally beneficial for your health. ;Bulking agents: Bulking agents are additives used to increase to bulk of a food without affecting its nutritional value. ;Colours: Colourings are added to food to replace colours lost during preparation, or to make food look more attractive. ;Colour retention agents: In contrast to colourings, colour retention agents are used to preserve a food's existing colour. ;Emulsifiers: Emulsifiers allow water and oils to remain mixed together in an emulsion, as in milk, mayonnaise and ice cream. ;Flavours: Flavours are additives that give food a particular taste or smell, and may be derived from natural ingredients, or created articially. ;Flavour enhancers: Flavour enhancers enhance a food's existing flavours. ;Flour treatment agents: Flour treatment agents are added to flour to improve its colour or its use in baking. ;Humectants: Humectants prevent foods from drying out. ;Preservatives: Preservatives prevent or inhibit spoilage of food due to fungi, bacteria and other microorganisms. ;Propellants: Propellants are any substances used to expel food from its container. ;Stabilizers: Stabilizers, thickeners and gelling agents work with emulsifiers to give foods a good texture, like Agar, or the pectin used in jam. ;Sweeteners: Sweeteners are added to foods for flavoring. Other sweeteners than sugar are added to lower the calories in food, or because they have beneficial effects for diabetes and tooth decay.