Food Preservation

Prevent spoilage and waste: Food preservation is important in preventing spoilage and food waste due to microbial growth, enzymatic action, or oxidation.
Retaining color, taste, and nutritional value: It is important to preserve food to retain the color, taste, and nutritional value for a longer period.
Prolong Shelf Life: Preservation methods help prolong the shelf life of food products, which allows us to use them for a longer period.
Reduce Loss: Preservation helps in reducing the loss of food due to spoilage, handling and other factors.
Increase food supply: Food preservation methods allow for an increase in food supply by making the food products available for a longer period.
Prevent food contamination: Preservation techniques help in preventing food contamination due to microbes, which can make it unfit for human consumption.
Making food available: Preservation makes sure that the food is available for a longer period and is not limited to only the harvest season.
To save money: Preservation can help save money, as you can utilize seasonal food for a longer period, and need not buy them often.
Control price during oversupply: Preservation methods also help in controlling the price of the produce during conditions of oversupply.

Preservative Action: Salt acts as a preservative due to its ability to inhibit microbial growth.
High Osmotic Pressure: Salt creates a high osmotic pressure, which draws moisture from the microbial cells, leading to plasmolysis and cell death.
Dehydration: It also helps in dehydrating food and microorganisms.
Formation of chloride ions: Salt ionizes to yield chloride ions, which are harmful to microorganisms.
Reduces Oxygen solubility: It reduces the solubility of oxygen in water, which in turn sensitizes the cells against CO2.

Oil, salt, vinegar, and lime juice are commonly used substances that are used for preserving pickles, due to their anti-microbial nature.

Some commonly used Class II chemical preservatives for fruit and vegetables are Potassium metabisulphite (KMS) and Sodium Benzoate.