Chemicals added during the processing of food to help preserve them, to assist in their manufacture, or to improve their taste, texture or appearance. Some categories of food additives include:

• Colourings (E100-180)
• Preservatives (E200-297)
• Antioxidants (E300-321)
• Emulsifiers, stabilizers and thickeners (E322-495)
• Acids, bases and related materials (E500-529)
• Anti-caking agents (E530-585)
• Flavour-enhancers and sweeteners (E620-640)
• Glazing agents (E900-914)
• Flour treatments and bleaching agents (E920-928)
• Packing gases (E941-948)
• Sweeteners (E950-967)
• Miscellaneous (E999-1518).

E numbers are the numbers allocated by the European Union for approved products.

Flavourings form the largest group of food additives, but government controls over these substances are often lacking because of the very small quantities used. Sometimes just a few molecules are needed to obtain a powerful flavouring effect.

Many individuals and consumer groups are concerned about the widespread use of artificial food additives. Large numbers of people are known to be sensitive to these chemicals. For instance sulphur-based preservatives may trigger asthma attacks, and digestive disturbances, and colourings have been linked with hyperactivity in children. One of the greatest concerns is the possible 'cocktail effect' of consuming numerous additives in combination. Government regulations only require the testing of additives singly, not in combination, and the safety testing is usually left to the additive manufacturing company itself.