Chemical substances can play an important role in food production and preservation. Food additives can, for example, prolong the shelf life of foods; others, such as colours, can make food more attractive. Flavourings are used to make food tastier. Food supplements are used as sources of nutrition
Food packaging materials and containers such as bottles, cups and plates, used to improve food handling and transport, can contain chemical substances such as plastic, elements of which can migrate into food. Other chemicals can be used to fight diseases in farm animals or crops, or can sometimes be found in food as a result of a production process such as heating/cooking or decontamination treatment.
Some plants and fungi naturally produce toxins that can contaminate crops and be a concern for human and animal health. People can also be exposed to both naturally occurring and man-made chemical compounds present at various levels in the environment, e.g. in soil, water and the atmosphere. Examples include industrial pollutants such as dioxins and PCBs. A variety of metals can be present naturally in the environment or as a result of human activity.