2013-11-02 by wsdchemicalpvc-additive is used to improve food quality , extend the shelf life of food , easy food processing and increasing food nutrients a class of chemical synthetic or natural substances. Food additives contributed greatly to the development of the food industry , and known as the soul of the modern food industry , mainly for the food industry is that it brings many benefits. 1 conducive to preservation , to prevent deterioration 2 . Improve food sensory properties 3 . Maintain or enhance the nutritional value of food 4 . Increasing food variety and convenience 5 . Favorable food processing, to adapt production mechanization and automation 6 . Meet other special needs practical , do not use a greater risk of preservative , which is often due to bad food poisoning caused by a disease . In addition, the preservative in addition to prevent food spoilage , but also can kill bacteria Aspergillus toxigenic microorganisms , which is undoubtedly beneficial to human health . Safety of food additives usage: without any toxic effects on health or adversely affect the amount of food additives , with the quality of daily intake per kilogram (mg) to indicate that the mg / kg. Now commonly used in food colorings include two categories: natural pigments and synthetic pigments . Natural pigments from natural products , mainly extracted from the plant tissue , including some from animal and microbial pigment. Synthetic pigment is artificial chemical synthesis of the obtained organic pigments, mainly coal tar isolated aniline dyes made from raw materials . In a very long period of time reporting process where food additives , because people do not realize the dangers of synthetic pigment and synthetic pigment with natural pigments , compared with bright color , strong coloring , stable and cheap, etc. , in many countries commonly used in the food processing industry, synthetic pigment .