Maharashtra Board Class 5 EVS Part I Chapter 13 Methods of Preserving Food PDF Download

Methods Of Preserving Food

We need wheat, rice, pulses, etc. throughout the year. But their crops get ready only at certain times of the year. In order to have the grain available throughout the year, one season's crop must be stored and protected till the next season.

Different foodstuffs are produced in different places. They have to be made available in good condition to people at long distances. For example, it must be ensured that eggs, milk and milk products remain in good condition during transport from the dairy or poultry farm till they reach their users.

Various kinds of papads, jams and pickles, onions, fish and masalas are prepared and preserved for the whole year in many homes. Nowadays, we can buy such ready products in the market, too.

Different fruits and vegetables are available in abundance in different seasons. They also taste their best in that season. To prevent these large quantities of fruit and vegetables from getting spoiled and to enjoy them all year round, we make efforts to preserve them.

To avoid having to go to the market for provisions again and again, we store what we need for several days in our house. If the food prepared for one meal is not finished, then, we use certain methods of keeping it from spoiling, in order to have it again the next time or the next day.

Can You Tell?

Talk to the elderly people in your family to find the answers to the following questions, with reference to the foodstuffs mentioned below:

Milk, vegetables, grains, flours, sugar, jaggery.

(1) When do we say that the foodstuff is spoiled? What changes are seen in it?

(2) Is the time in which foodstuffs get spoiled different in different seasons?

(3) Which foodstuffs spoil most quickly?

(4) What measures are taken to keep the foodstuffs in the house in good condition, for as long as possible?

If we know the reasons why foodstuffs go bad, we would know what to do to keep them from spoiling. From the information you obtained you must have gathered the following:

(1) In winter, i.e. in the cold weather, foodstuffs keep longer. If they are kept in a refrigerator or kept cold on ice, they keep even longer.

(2) Grains are dried in the sun before storing. Onions and potatoes are kept to dry in the open air in summer and then stored in a dry place.

(3) If we boil milk it does not get spoiled immediately. Curries and vegetable preparations are brought to a boil to prevent them from spoiling till the next meal.

(4) Milk, mango pulp are foods that spoil quickly.

(5) Our food has to be kept away from ants, cockroaches, other insects, mice, rats and cats.

Teacher's Note

In India, many families store rice and wheat in sealed containers to protect them from insects. We also keep milk in the fridge to keep it fresh for longer.

Exam Trick

Remember: Cold weather = food stays fresh longer. Just like ice keeps lassi cold, fridge keeps food fresh. Write this in your answer.

Points to Remember

Foodstuffs spoil faster in warm weather and slower in cold weather.
Drying grains and vegetables removes water and stops spoiling.
Boiling food kills germs and keeps it fresh for one more meal.
Milk, mango pulp and wet foods spoil very quickly.
Keep food away from insects, rats and cats.

Try This

(1) Divide a chapati into three pieces.

(2) Put one piece in a closed box.

(3) Roast the second piece on a hot pan to make it crisp without charring it. Let it cool and put it in a box.

(4) If possible, put the third piece in a box and put it in the fridge.

Observe these pieces every morning and evening for two-three days.

What Do You See?

We see white, black or greenish fibres like cottonwool growing on the piece of chapati placed in the closed box. It also starts smelling. Whereas, for several days, we see no such changes in the crisp piece of chapati or the one that was put in the fridge.

Why Is This So?

The cottonwool-like fibrous growth on the chapati is a kind of fungus. A fungus is a type of micro-organism.

Spores of the fungus are present in air and water. The chapati in the box created favourable conditions for the growth of the fungus - availability of food, water, air and warmth. That is why, the fungus grew on the chapati in the box.

Teacher's Note

You can see this fungus growth in your own home. Keep bread or chapati in a wet place and after a few days you will see green or black spots on it. This is how fungus grows.

Exam Trick

Remember: Fungus needs four things - food, water, air and warmth. If you remove any one of these, fungus cannot grow. Write all four in your answer.

Points to Remember

Fungus is a type of micro-organism that grows on food.
Fungus needs food, water, air and warmth to grow.
Dry food does not get fungus because it has no water.
Cold food does not get fungus because it has no warmth.
Fungus makes food smell bad and look dirty.

Food And Micro-Organisms

You know that micro-organisms are present all around us in the air as well as in water. Usually, air, moisture and warmth are available where food is kept. It means that it is always possible for micro-organisms to grow rapidly in our food or foodstuffs. We cannot see them, but if they begin to grow, our food gets spoiled. Such spoiled food can cause a stomachache, diarrhoea, vomiting, etc. The nutrition value of such food is also reduced. Sometimes, it can even threaten life.

Teacher's Note

Micro-organisms are so small that we cannot see them without a microscope. But they are everywhere around us. When we eat spoiled food, these germs make us sick with stomach pain.

Exam Trick

Remember: Micro-organisms = germs = very small living things = cannot see with eyes. When they grow, food gets spoiled and we get sick.

Points to Remember

Micro-organisms are very tiny living things in air and water.
We cannot see micro-organisms without a microscope.
Micro-organisms grow fast when food has water, air and warmth.
Spoiled food with growing micro-organisms causes sickness.
Spoiled food loses its nutrition and can even be dangerous.

Methods Of Food Preservation

Drying

When we dry foodstuffs, their water content is lost. This method is used to preserve foodstuffs like papads, kurdai, sandage, wheat, daals, etc.

It means that to preserve foodstuffs, the micro-organisms in them should be destroyed. Also, they must be placed in conditions in which micro-organisms will not grow again.

Cooling

When food is placed in a refrigerator, micro-organisms do not get the warmth they need for growth.

Boiling

When foodstuffs are boiled, the micro-organisms in them get destroyed.

Placing In Airtight Cans

When foodstuffs are preserved in airtight containers, the micro-organisms are first destroyed and it is ensured that water or air will not enter the foodstuff.

Teacher's Note

In villages across India, people dry vegetables and meat in the sun to preserve them for months. They also use salt and oil to keep pickles fresh all year.

Exam Trick

Remember the four methods: Dry it, Cool it, Boil it, Seal it. Each one stops micro-organisms from growing. Write these four methods in your answer.

Points to Remember

Drying removes water so micro-organisms cannot grow.
Cooling in fridge stops micro-organisms by removing warmth.
Boiling kills all micro-organisms in food.
Airtight containers stop air and water from entering food.
All four methods either kill germs or stop them from growing.

Try This

Make A Pickle

Materials required: A glass jar, a knife, a spoon, 7-8 lemons, a quarter bowl of salt, 2 teaspoons red chilli powder, \(\frac{1}{2}\) bowl sugar.

Procedure: Clean and dry the jar. Cut each lemon into 8 pieces. Put these pieces in the jar and add salt, sugar and chilli powder. Mix the ingredients well with a dry wooden or steel spoon. Tie a clean piece of cloth over the mouth of the jar and keep it in the sun for about 10 days. Stir it every day with a clean dry spoon. Your hands too should be clean and dry. Enjoy your pickle.

Preservatives

Certain substances are added to jams and pickles to preserve them for a long time. They are called preservatives. Sugar, salt, asafoetida (hing), mustard, oil and vinegar are examples of preservatives.

Teacher's Note

Your mother or grandmother probably makes pickles at home using salt and oil. These are natural preservatives that have been used in Indian homes for thousands of years.

Exam Trick

Remember: Salt and sugar are preservatives. They stop micro-organisms from growing. That is why pickle stays fresh in a jar for many months.

Points to Remember

Preservatives are things we add to food to keep it fresh.
Salt, sugar, oil and vinegar are common preservatives.
Asafoetida (hing) and mustard also preserve food.
Pickles and jams stay fresh for many months because of preservatives.
Preservatives stop micro-organisms from growing in food.

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