Preservation of Food by Mustard oil and Vinegar, Chemicals, Pasteurisation, Air-tight packets

Question 1 Name food material which are preserved by mustard and vinegar?

Question 2 Name food material which are preserved by using chemicals as preservatives?

Question 3 Name food material which are preserved by pasteurisation?

Question 4 Name food material which are preserved in air-tight packets?

Question 5 Name some preservatives which are used in the preservation of fruits as jam and jellies?

Question 6 How do you preserve food by mustard oil and vinegar?

Question 7 How do you preserve food by using special chemicals?

Question 8 How do you preserve food by Pasteurisation?

Question 9 How do you preserve food in air tight -packets?

 

Also Read NCERT Solutions Class 8 Science

Preservation of food by mustard oil and vinegar

They are used as preservative for the preservation of fruits and vegetables in the form of pickles. The use of mustard oil or vinegar prevents the spoilage of fruits and vegetable because food-spoiling bacteria cannot live in such an environment.

They are used as preservative for preserving fruits such as raw mango, amla and lemon in the form of their pickles.

Preservation of Food by using special Chemicals as Preservatives

The three special chemicals which are used as preservative in the preservation of food are: Sodium meta bisulphite, sodium benzoate and citric acid. They are used to preserve jams, jellies, juices and squashes so as to save the food from spoilage. Citric acid is used as a preservative in confectionary. These special chemicals kill the food spoilage bacteria but they do not harm us.

Preservation of Food by Pasteurisation

The method of pasteurisation is used for the preservation of milk in big diaries. It involves the process of heating followed by quick cooling.

First the milk is heated for 15 to 30 sec to kill most of the bacteria present in it. This hot milk is cooled very quickly to a low temperature to prevent any remaining bacteria from growing further. And then milk is stored in cold. Pasteurised milk can be consumed without boiling because it is free from harmful micro-organism. The milk that comes in packets also does not get spoiled for a fairly long time. This is because it is pasteurised milk.

Preservation of food by Air-tight Packets

Dry fruits and even vegetables are sold in sealed, air-tight packets to prevent the attack of micro-organism on them. This helps the dry fruits and vegetable to remain unspoiled for a longer time.

 

Other Notes from Chapter 2 Micro Organisms Friend and Foe Micro-Organisms Groups of Micro Organism Where do Micro Organism Live Useful Micro organism Making of Curd and Bread Commercial Use of Micro organism Medicinal Use of Micro oragnaism Increasing Soil Fertility Cleaning the Environment Harmful Micro Organism Carriers of Disease causing micro organism Disease Causing Micro organisms in Animals Disease Causing Micro-Organism in Plants Food poisoning Preservation of Food Preservation by sun-drying, Heating, Cooling Preservation by Deep Freezing,Common Salt, Sugar Nitrogen Fixation Nitrogen Cycle