Preservative is a substance or a chemical that is added to products such as food, beverages, pharmaceutical drugs, paints, biological samples, cosmetics, wood, and many other products to prevent decomposition by microbial growth or by undesirable chemical changes.
Preservatives are substance which when added to food, is capable of inhibiting, retarding or preventing the process of fermentation, acidification or other decomposition of food by the growth of microorganisms.
They are natural or synthetic chemical that is added to foods or pharmaceuticals to retard spoilage, whether from microbial growth, or undesirable chemical changes. In general, preservation is implemented in two modes, chemical and physical. Chemical preservation entails adding chemical compounds to the product. Physical preservation entails processes such as refrigeration or drying.
Preservative or food additives reduce the risk of food-borne infections, decrease microbial spoilage, and preserve fresh attributes and nutritional quality. Some physical techniques for food preservation include dehydration, UV radiation, freeze-drying, and refrigeration. Chemical preservation and physical preservation techniques are sometimes combined.
Food preservatives can be classified into two groups:
- Class I: Includes preservatives obtained from natural sources i.e. Natural preservants like table sugar, salt and vegetables.
- Class II: Includes chemical preservatives like sodium benzoate, sodium meta-sulphide etc.
Artificial preservatives are the chemical substances that stops or delay the growth of bacteria in foods, spoilage and its discoloration. These artificial preservatives can be added to the food or sprayed on it. It includes antimicrobial agents, antioxidants and chelating agents. They can be organic (Benzoates, Propionates and Sorbates) or inorganic (Sulphites, Nitrates, Nitrites etc.).
E.g. there are a number of artificial preservatives used when baking bread, most commonly used ones are calcium propanoate and propionic acid. Calcium propanoate is a naturally occurring chemical in dairy products that is produced artificially to serve as an additive in food products. More calcium propanoate in the loaf is often marketed as “more calcium” in breads. Propionic acid inhibits the growth of bacteria in food, therefore extending its shelf life.
Although artificial preservatives have some advantages like preservation of food and food products as well as limiting the food borne illness, they also have adverse effects on health such as deadly allergic reactions by sulfites, increased risk of cancer etc.
Not all preservatives are artificial. Some of them comes from natural source and are called Natural preservatives, which include rosemary and oregano extract, vinegar, alcohol, salt, sugar, diatomaceous earth and castor oil etc. Garlic and clove along with honey, ginger and cinnamon, belong to the family of flavorful natural food preservatives.
E.g. Salt has been used from centuries to preserve meats and vegetables. Microorganisms that spoil food tend grow in water, however, salt dehydrate microbes through process of osmosis and halts their growth and prevents them from growing. Salt also prevents yeast and bacteria from decaying the food. In same way sugar absorbs water and prevents microbial growth.
Clove has high amounts of phenolic compounds, which have antioxidant properties, they keep food from spoilage by preventing the growth of fungus and bacteria.
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