additive

In food, any natural or artificial chemical added to prolong the shelf life of processed foods (salt or nitrates), alter the colour, texture, or flavour of food, or improve its food value (vitamins or minerals). Many chemical additives are used and they are subject to regulation, since individuals may be affected by constant exposure even to traces of certain additives and may suffer side effects ranging from headaches and hyperactivity to cancer. However, it can be difficult to know how to test the safety of such substances; many natural foods contain toxic substances which could not pass the tests applied today to new products.

Food companies in many countries are now required by law to list additives used in their products. Within the European Union, approved additives are given an official E number.