A food additive is any substance not normally consumed as food but added to food either intentionally or by accident. Intentional additives are substances put into foods on purpose, whereas accidental (incidental) additives are substances that may get into the food by accident before or during food processing. Some intentional additives include nutrients, preservatives, colors, and antioxidants, and incidental additives include packaging material, metals, veterinary drugs, and pesticides.
From the beginning of time, humans have invented ways to preserve food after harvest and slaughter to make it last longer, be more palatable, and, in recent times, be more readily available for use. Drying and fermentation are ancient practices of food processing. Drying and salting techniques were widely used, and in some countries salt for flavor and preservation became so valued that it was used as a form of payment. The French chef Nicholas Appert found that one could fill bottles with food and after the bottles were sealed with corks, they could be heated in boiling water, and this process made foods last for some time. Thus was invented the food process of canning or appertization.
The objectives for food processing are to make food look, taste, and smell as though it has not been preserved and to allow the food to be safely eaten at a later date. In recent times, the objectives have been modified to include the development of totally new food products that offer a higher level of convenience to the consumer. To accomplish these objectives, food science has found means to stop microbial growth and chemical reactions, however, not without some destruction of flavor, color, texture, and nutritive value. The advantages of food processing are that these methods make foods safer (inhibit microbes), enhance nutrient value of food (e.g., adding iodine to salt or skimming of fat from milk and enrichment or fortification of foods), allow choice (regular and reduced fat, reduced cholesterol, fat-free), increase sensory properties of food (air in ice cream), provide convenience, and offer variety (unusual and ethnic foods).
There are some drawbacks of food processing. Food processing causes some nutrient loss compared with the raw material. Some food products seem to have little by way of nutrient benefit for the consumer, but may provide a degree of consumer satisfaction. Finally, packaging of processed foods has created environmental and energy concerns; for example, potato, the common staple, requires little energy for storage unless it is processed and frozen, as demanded by consumers. The use of additives is an important part of food processing.
The 1958 Food Additives Amendment to the Food, Drug, and Cosmetic Act requires that if food processors wish to add a substance to food, they must submit a petition to the Food and Drug Administration (FDA) with documentation on chemistry, use, function, and safety. Many substances were exempted from complying with the FDA procedure because there were no known hazards in their use at that time. The list of substances became known as the GRAS (generally recognized as safe) . Since 1958, some substances on the GRAS list have been reviewed, and a few, such as cyclamate and red dye #3, were removed because new information linked them to health problems. However, many of the chemicals on the GRAS list have not been rigorously tested and it is likely they will not be tested because of their long-time histories of use without any proof of harm or because their chemical structures do not suggest they could cause harm. One of the standards an additive had to meet in order to be placed on the GRAS list was that it must not have been found to be a carcinogen in any test on animals or humans.
Another broad way to classify additives is based on whether the substance is synthetic or natural. Natural additives refer to the group of substances of plant, or, in some cases, animal origin. Synthetic food additives must be extensively evaluated for toxicity before being allowed for use in food.