Close-up of the ingredients label from a packet of potato crisps (chips), showing the number of additives in addition to the basic ingredients of potatoes, vegetable oil and salt. The antioxidants E320 and E321 are used as preservatives to prevent the oil from becoming ransid. The E number system is used throughout the food industry to denote a wide range of additives including: preservatives, flavour enhancers, colourings and emulsifiers. Each additive is denoted by an individual E number. Some food additives have been implicated in a range of medical conditions from hyperactivity in children to cancers in adults.