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.
Some methods involve the use of salt, sugar or vinegar, which are sometimes considered to be foods rather than preservatives.
Preservatives have been used since prehistoric times. Use of preservatives other than traditional oils, salts etc. in food began in the late 19th century, but was not widespread until the 20th century. E.g. Smoked meat has phenols and other chemicals that retard spoilage.
Characteristics of preservatives
- They should be harmless to human beings
- They should inhibit the growth of microorganisms when used in trace amounts.
Needs of preservatives in food
- Inhibit the growth of microorganisms like bacteria and fungi.
- Increase shelf life.
- Preserve the appearance of food
- Preserve the food characteristics like odor, taste and food is preserved for a long time
Foods preservatives help maintain the freshness and shelf life of such food products because without them, they would spoil quickly due to exposure to air, moisture, bacteria, or molds. Either natural or synthetic substances may be added to avoid or delay these problems.
Importance of preservatives
Food preservatives are essential for many reasons. They are used to:
- Maintain consistency and texture of food.
- Improve or retain nutritional properties
- Delay spoilage
- Enhance flavors, textures, and color
- Make food palatable, attractive
Types of Food preservatives can be grouped 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.
Although large number of chemicals have been described that show potential as food preservatives, only a small number are allowed in food products, due in large part to the strict rules of safety adhered to by the Food and Drug Administration (FDA) and to a lesser extent to the fact that not all compounds that show antimicrobial activity in vitro do so when added to certain foods.
Sugar and salt are the earliest natural food preservatives that very efficiently drops the growth of bacteria in food. To preserve meat and fish, salt is still used as a natural food preservative.
Preservatives are generally recognized as safe, or GRAS (Generally regarded as safe), in the quantities in which they are allowed in individual food products. Food preservatives plays vital role in preventing deterioration of food, protecting against spoilage from mold, yeast, life-threatening botulism and other organisms that can cause food poisoning.
Artificial preservatives are the chemical substances that stops of delayed the growth of bacteria, spoilage and its discoloration. These artificial preservatives can be added to the food or sprayed on the food. It includes antimicrobial agents, antioxidants and chelating agents.
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