Question

5 different food preservatives used to preserve food​

Answer 1

Answer:

To preserve the natural characteristics of food

To preserve the appearance of food

To increase the shelf value of food for storage.

Answer 2

The process by which spoilage of food is prevented using chemical or physical methods is called food preservation.

The most common methods used for food preservation are described below:

1. Chemical method :

• Food can be preserved by using certain chemical substances which can check the growth of microorganisms. Such chemical substances are called food preservatives. Most chemical preservatives remove oxygen from the food items. This helps in preventing microbial growth. Sodium benzoate, citric acid and potassium metabisulphite are common food preservatives. Sodium benzoate is used for preserving fruit juices and squashes. Potassium metabisulphite is used for preserving cut fruits, jams, jellies, etc. Citric acid is used as a preservative in confectionaries.

2. Preservation by common salt :

• For ages, people have preserved fish and meat by salting. Meat and fish are covered with common salt to prevent the growth of microbes. Salting draws out water (moisture) from the food, thus, prevents microbial growth and reproduction. Salting is also used to preserve amla, raw mangoes, tamarind, etc.

3. Preservation by sugar :

• Sugar reduces the moisture content of the food, thus, inhibits the growth of food-spoiling microorganisms. Jams, jellies and squashes are preserved by sugar.

4. Preservation by oil and vinegar :

• Oil and vinegar prevent the growth of food-spoiling microorganisms. Mustard oil and vinegar (sirka) are widely used as preservatives for fruits and vegetables in the form of pickles. Meat and fish are also preserved by this method.

5. By cooling or freezing :

• Foods like fruits, vegetables, meat and cooked food are kept at low temperature in the refrigerator or deep freezers to prevent their spoilage. Low temperature prevents the spoilage of food because it retards the growth of microorganisms.

6. Canning or vacuum packing :

• Food items are first heated at a high temperature to kill bacteria and their spores to obtain sterilised food. The sterilised food is then sealed in.airtight cans to prevent reinfection by microorganisms. This air-free packing is also called vacuum packing.

7. Preservation by heating :

• Heating kills many microorganisms and prevents the food from spoilage. Some food items are preserved only through heating. For example, we can prevent the spoilage of milk for long time only through boiling. Milk is partially sterilised by heating it for a short time around 1-2 seconds at a temperature exceeding 135 °C. This is called Ultra Heat Treatment (UHT).