Consumers normally consider that the term "food additive" refers to almost all substances, primarily chemical in nature, added to foods during production, manufacture, packaging or storage. However, as defined under the Canadian Food and Drug Regulations, a "food additive" means any substance, including any source of radiation, the use of which results or may reasonably be expected to result in it or its byproducts becoming a part of or affecting the characteristics of food. Based on this definition, the term does not encompass materials such as salt, sugar and starch used as ingredients of food or commonly sold as food products. Certain other substances are excluded from the definition because they fall into categories covered separately under the Food and Drug Regulations and are thus subject to other controls. These ingredients include vitamins, mineral nutrients, amino acids, spices, seasonings and flavouring preparations, as well as agricultural chemicals, food-packaging materials and veterinary drugs.
Food additives are controlled by means of a positive listing system of permitted substances. If an additive is not on this list, it may not be used in a food offered for sale in Canada. The permitted list names the additive and lists the foods in which it may be used and the levels of use. The list encompasses some 390 substances classified into 154 tables based on the function of the additives. Food additives perform a variety of functions in food manufacture. For each function a number of different additives are permitted to allow manufacturers the choice necessitated by variations in food properties, processing variations and market availability of the additive.
The function of additives and their exact mode of action is complex; however, for the functions noted, the additives do what is implied in the table title. For example, certain food products (eg, salt, dried-powder mixes) tend to absorb moisture from the atmosphere, which causes them to clump or cake. Anticaking agents prevent this from occurring and allow the food product to remain free running. Similarly, firming agents maintain the texture of a number of processed foods, such as fruits and vegetables, which would otherwise go soft as a result of heat treatment during processing.
Dough conditioners modify the strength of flour, improve the handling properties of dough and reduce mixing time, resulting in better texture and volume in bakery products. Colouring agents are added to foods to give them an appetizing and attractive appearance. Emulsifying, gelling, stabilizing and thickening agents modify texture and impart a desired consistency to foods. Such agents may also be used to help keep suspended food particles from separating and settling to the bottom (eg, the chocolate in chocolate milk) and to modify the consistency of products (eg, frozen desserts).
Because food technology is forever changing and new foods are constantly under development, there is a continual demand for new food additives. In Canada, for a new substance to be added to the listing of permitted additives, a submission of information is required, the format of which is outlined under the Food and Drug Regulations. This submission must include a description of the food additive, its method of manufacture, chemical and physical properties, composition and specifications. It must also include data establishing that the additive will have the intended effect and detailed reports of tests made to establish the safety of the additive under the conditions of use recommended. If no concerns are raised during the evaluation of this information, the additive can be added to the positive list of permitted additives.
Additives may be removed from the positive list of substances based upon evidence of possible hazard to the consumer. Examples of substances which are no longer permitted in Canada are nitrogen trichloride (bleaching agent in flour), cobaltous chloride (foam-stabilizing agent in beer), benzyl violet (colour in foods) and potassium bromate (flour treatment agent).
Food additives have been and continue to be a controversial subject. Although it would be possible to produce and manufacture some foods without using these substances, many of the products currently available would not be possible without them. For example, certain convenience "ready-to-serve" products and foodstuffs needing preservation require the use of food additives in the absence of other techniques that can achieve the same technical effect.