This article may be merged with Food additive where it does not duplicate that article, then deleted.

Preservatives, additives and colourings are all related to food, chemicals,etc. A preservative is a natural or synthetic chemical that is added to products such as foods, pharmaceuticals, paints, biological samples, etc. to retard spoilage, whether from microbial growth, or undesirable chemical changes.

Preservatives may be added to wood to prevent the growth of fungus as well as repel insects and termites. Typically copper, borate, and petroleum compounds are used. Food addictives regulations require the preservatives. Preservative food additives are often used alone, or in conjunction with other methods of food preservation. A distinction is sometimes made between anti-microbial preservatives which function by inhibiting the growth of insects, bacteria and fungi, and antioxidants, which inhibit the oxidation of food constituents. Common anti-microbial preservatives include sodium nitrate, sodium nitrite, sulfites, (sulphur dioxide, sodium bisulfate, potassium bisulfate, etc.) and disodium EDTA. Antioxidants (keeps food from becoming rancid, browning or developing black spots) include BHA and BHT. Other preservatives include formaldehyde (usually in solution), glutaraldehyde, diatomaceous earth (kills insects), ethanol and methylchloroisothiazolinone. The benefits and safety of many artificial food additives (including preservatives) are the subject of debate.

Some methods of food preservation involve the use of salt, sugar or vinegar, which are sometimes considered to be foods rather than additives.

In our normal life it’s impossible to eat food without preservatives; without such preservatives, food safety problems would get out of hand. Bread would get moldy, and salad oil would go rancid before it’s used. Manufactures add preservatives mostly to prevent spoilage during the time it takes to transport foods over long distances to stores and to our kitchens. Preservatives may not be used to deceive a consumer by changing the food to make it appear than it is.

Food additives are substances added to food to preserve it, or to improve its flavour and appearance. Some additives have been used for centuries; for example, when preserving food by pickling (with vinegar), salting, as with bacon, or using sulfur dioxide as is common in wine. However, with the advent of processed foods in the second half of the 20th century, many more additives have begun to be used, of both natural and artificial origin.

Numbering To regulate these additives, and inform consumers, each additive is assigned a unique number. Initially these were the "E numbers" used in Europe for all approved additives. However, the numbering scheme has been adopted and extended by the Codex Alimentarius Committee to internationally identify all additives, regardless of whether they are approved for use. E numbers are all written with an "E" in front, but other countries use only the number whether the additive is approved in Europe or not. For example, acetic acid is additive 260, so it is written as E260 on products sold in Europe. Additive 103, alkanet, is not approved for use in Europe and so does not have an E number, although it is approved for use in Australia and New Zealand. Categories Food additives can be divided into several different groups, although there is some overlap between them. Acids Food acids, especially vinegar and citric acid, are added to make the flavour of foods "sharper", and also act as preservatives and antioxidants. Acidity regulators Acidity regulators are used to change or otherwise control the acidity and alkalinity of foods. Anticaking agents Anticaking agents keep powders such as milk powder flowing freely, rather then sticking together in lumps. Antifoaming agents Antifoaming agents reduce or prevent foaming in foods. Antioxidants Antioxidants such as vitamin C act as preservatives by inhibiting the effects of oxygen on food, and are generally beneficial for your health. Bulking agents Bulking agents are additives used to increase to bulk of a food without affecting its nutritional value. Food coloring Food colorings are added to food to replace colours lost during preparation, or to make food look more attractive. Colour retention agents In contrast to colourings, colour retention agents are used to preserve a food's existing colour. Emulsifiers Emulsifiers allow water and oils to remain mixed together in an emulsion, as in milk, mayonnaise and ice cream. Flavours Flavours are additives that give food a particular taste or smell, and may be derived from natural ingredients, or created articially. Flavour enhancers Flavour enhancers enhance a food's existing flavours. Flour treatment agents Flour treatment agents are added to flour to improve its colour or its use in baking. Humectants Humectants prevent foods from drying out. Preservatives Preservatives prevent or inhibit spoilage of food due to fungi, bacteria and other microorganisms. Propellants Propellants are any substances used to expel food from its container. Stabilizers Stabilizers, thickeners and gelling agents work with emulsifiers to give foods a good texture, like Agar, or the pectin used in jam. Sweeteners Sweeteners are added to foods for flavoring. Other sweeteners than sugar are added to lower the calories in food, or because they have beneficial effects for diabetes mellitus and tooth decay. The color of food is considered important in its enjoyment. Coloring adds interest and appeal: Heinz's recent release of green ketchup is only the tip of the iceberg. While foods like Froot Loops are obviously artificially colored, few people know that oranges can be as well. Color variation in foods throughout season and the effects of processing and storing often make color addition necessary to maintain the expected color. Some of the primary reasons include: · Offsetting color loss due to light, air, extremes of temperature, moisture, and the storage conditions. · Masking natural variations in color. · Enhancing naturally occurring colors. · Providing identity to foods. · Protecting flavors and vitamins. Food colorings are tested for safety by various bodies around the world. In the United States, FD&C (standing for the Federal Food, Drug, and Cosmetic Act) numbers are given to approved dyes, while in the European Union E numbers are used. Natural food dyes Caramel coloring is found in Coca-Cola and other cola products. It is made from caramelized sugar. Annatto is a reddish-orange dye made from the seed of a tropical tree. Chlorella is green, and derived from algae. Cochineal is a red dye derived from cochineal insects. Beet juice, turmeric, saffron and paprika are also used as colorants.

Health problems Many of the artificial food colorings cause reactions in sensitive individuals ranging from hyperactivity to depression to asthma-like symptoms. Dr. Benjamin Feingold pioneered research in the field and founded an organization devoted to helping sensitive individuals stay away from artificial colors, flavors, and preservatives. Individuals who have asthmatic symptoms when exposed to Yellow Dye No. 5, also known as Tartrazine, can also be allergic to non-steroidal anti-inflammatory drugs, such Other uses Some artists have used food coloring as a means of making pictures, often using them to paint the human body.