Close-up of the ingredients label from a packet of chewy sweets of assorted flavours. In addition to the assortment of fruit juices used to flavour each packet of sweets, a number of additives are used to give each type a distinctive colour. Each chemical colouring agent used is denoted by a peculiar E number. E numbers are used throughout the processed food industry to denote a wide range of additives including: preservatives, flavour enhancers (eg monosodium glutamate), colourings and emulsifiers. Certain chemical additives in foodstuff have been implicated in a range of medical conditions from hyperactivity in children to cancers in adults.