To prevent the putrefaction of many products by such as food, pharmaceutical drugs, paints, biological samples, beverages, cosmetics, wood and hundreds of other goods the microbial growth or by unwanted chemical changes, the chemicals or substances are being used and these are known as preservatives. On the whole these chemicals are being applying in two different manners, chemical and physical. Chemical preservation means that preserving the products by adding the chemical compounds in them. On the other hand physical preservation means that by keep the products in refrigerators, in deep freezer and in drying machines for refrigeration or drying.
Additives that are being used in food to preserve it, have reduced the danger of disease which can happen due to foodborne, at has also diminish the microbial spoilage and also helping very in saving the qualities of food like its freshness and nutritional excellence. There are some other physical techniques to save the food from infections and from rooting and these methods are dehydrations, freeze-drying, UV-C radiations. There are many in cases in which people use both physical and chemical methods combines for this purpose.
The food specifically which has high content of fats can ruined with the oxidation process. Fats cannot bear the exposure to the oxygen and get sour or stale when get exposed to it. To slow down the oxidation process or to stop it there are antioxidants which can be used for the purpose. The ascorbic acid, normally known as vitamin C and acrobats are the most common antioxidants that are being used. They are being used very frequently in chips, oil and cheese. There are other antioxidants too such as propyl gallate, BHA, TBHQ and BHT. These components help to hold back the development of hydroperoxide. Ethanol and methylchloroisothiazolinone are some other preservatives.
There are other many agents which are working in deactivation of metal ions which start the process of oxidation in fats. Some very frequently used item are citric acid (and citrates), lecithin, disodium EDTA and tartaric acid.
There are some compounds target only vegetable and fruit and rot them such as citric and ascorbic acids, for example the acid which turns the surface of potatoes and apples is phenolase. Smoking entails food to expose to a number of phenols and they are antioxidants. There are also some natural preservatives which are rosemary extract, salt, sugar, alcohol, vinegar, castor oil and diatomaceous earth.
There are many traditional substance to save the food that have increased the concern of people of health in the past and those are sodium benzoate. People who have asthma problem are very sensitive with benzoate. This problem have make people to think about the reexamination of these food saving substances.
