5th Class Science Food Food


Category : 5th Class


This lesson will help you to:

  • Understand that our body needs food for energy and for growth.
  • Examine different types of food like fruits, vegetables and cereals.
  • Understand how we can fall ill if we do not keep our food safe and clean.



In this chapter we shall learn some more things related to food. As we already know that by having a contaminated and spoiled food we can fall ill. In this chapter we shall learn how the food gets spoils and how we can prevent our food from getting spoiled.


Historical preview

  • There were no tomatoes in Italian food. Peanuts in Thai food, or chili peppers in Indian food in the year 1450.



Spoilage of food is a state of deterioration of food in which the food no longer remains suitable for human consumption. So the spoiled food means that the food can no longer be taken as it has got very much deteriorated.



The food gets spoiled because of the attack of microorganisms depend upon food and they feast on the food when it is not attended. Worms, insects and bugs also spoil. One of the major causes of food spoilage is the storage of food in   warm places.



As soon as there is change in colour, flavor, odor and appearance, the food has started to get spoiled. The first thing which comes to our notice is the change in colour or the appearance of the food. The food either gets softer or harder than its normal state. For example, the fruits kept unattended for a few days will become softer. There is also a foul smell from a rotten food.                        


Some food items such as biscuits, pickles, cooked vegetables and boiled milk, etc., take some time to get spoiled as compared to uncooked vegetables and flesh, unattended fruits and milk. When we keep the food in a warm place for a long time there is growth of food spoiling micro-organisms at a faster rate. That is why the food kept in the refrigerator does not get spoiled very soon, as the temperature inside it is lower.



By taking some simple precautions we can save our food against spoiling. Some of these are:

  • The major cause of the food spoilage is its improper storage. If we keep the food and vegetables in warm place they will spoil quickly. So whenever we bring such things we should properly keep them in the refrigerator because low temperature slows down the growth of food spoiling bacteria.
  • Food like cereals, pulses and grains, etc., should be kept in airtight containers.
  • We should never keep the food at a dirty place.
  • We should keep on checking our refrigerator from time to time.
  • If one of the food items gets spoiled, we should immediately separate it from other food items as it can spoil rest of them too.
  • The seed inside a peach contains an almond-like nut which holds a popcorn gives off a toxic, lung-damaging gas when cooked.
  • Cherries ease inflammation and gout; and they may even help prevent arthritis.

Apart from these there are other techniques also which are used at homes and food manufacturing companies to prevent food spoilage. These are;

  1. Refrigeration: It is the most popular way of preserving the food as discussed above.
  2. Canning: In this method the food is boiled to kill any bacteria and then is sealed into a container.
  3. Dehydration: Dehydration means to take out the water from the food item. Most of the bacteria will die when dehydrated. But it changes the taste and texture of the food a bit.
  4. Pickling: Fruits and vegetables can be prevented through this method even for years. The acid used in this technique stops the bacterial growth.
  5. Chemical Preservation: It is one of the commercial methods used by the food manufacturing companies to prevent the food using nitrates, sorbic acid and sulphites, etc.

These are the things which we can keep in mind while we are at home. But when we are travelling we have to

preserve our food from heat and moisture.



Here are a few precautions which should be taken:

  • Always pack the eatables properly.
  • We should pack the food in airtight tiffin.
  • Vacuum sealing can also be used to protect the food from moisture.
  • Never pack rotten and old eatables. They can get spoiled and can also spoil other foods.
  • Pack different foods separately.
  • Before packing fruits wash them properly and pack after drying them.



We need to preserve food for the following reasons:      


  • By preventing our food from spoilage we can save a lot of food from getting wasted.
  • If we keep our food properly and do not let it get spoiled, we cannot fall due to spoiled food.
  • By preserving the food in a proper way we can preserve the nutritional value of food.



In earlier classes you have read about how a farmer grows the seeds and then he irrigates the fields. But till now we have discussed the farmers who give us vegetables and grains. There are a few more types of farmers such as: 

  • Dairy farmers: These farmers raise female cattle, goats and other milk giving animals. The milk/ then is transported to different places.
  • Poultry farmers; they raise chickens, ducks and turkeys for meat and eggs.
  • Field farmers: These are the farmers who grow vegetables, fruits, pulses and grains.

Not all the farmers own their fields. Only some of the farmers work on their own lands. The rest of the farmers we see in different places are the ones kept by original owners to cultivate their lands. Due to high costs of land and the materials used in agriculture all the farmers cannot afford their own lands.



We all know that our food comes from the fields. The farmers work in the fields and grow food for us. But do you know that the whole process of growing food, takes a long time and needs a lot of effort. Let us discuss the

Process of growing food step by step:

  • Ploughing: First of all the field is prepared to grow the food. Ploughing of soil is done so that the soil particles get enough air and become soft too. In earlier days ploughing was done by the traditional plough with the help of animals such as ox.


But now we have modern machines to plough the fields such as tractors which are attached to the plough making the process easy.

  • Sowing: After the soil has been made soft the next step is to sow the seeds. Any crop cannot be sown in any field. The crop to be grown depends upon the type of soil.


A few examples are:

  1. Alluvial soil which is rich in nutrients, is used for growing rice and sugarcane. This type of soil is found in North India.
  2. Black soil is suitable to grow wheat and cotton. It contains a large amount of clay.
  3. Mountain soil which is somewhat acidic in nature is suitable for growing tea and coffee in it.

The farmers get the seeds either from the seed shops or they use the seeds saved form the last year crops. The seeds come from adult plants to    make new.

  • Watering: After the seeds are grown, the next step is to water the seeds which later grow into small plants. The amount of water needed for a crop to grow depends upon the type of crop.



  • Weeding: Weeding means to remove weeds. Weeds are the unwanted plants which grow with the crops. The weeds use the nutrients and minerals from the soil the way the crop does. So it becomes important to remove them so that they do not compete with the crop for the nutrients which are important for 'It    the crop.

The major ways to get rid of the weeds is by hand picking or these days herbicides are also used.


  • Manure: It contributes to the fertility of the soil. Animal manures are mostly animal feces. Different types of manures have different properties.

There are also manures which are made from the remains of dead plants.



  • Spraying of insecticides: Insecticides are used to keep the plants away from any types of insects which may harm the crops.


  • Harvesting: After all this hardship the crop grows and then the harvesting is done.

So we can now say, that forming is not only about sowing the seeds and reaping the crop. Different things along with the seeds are also used such as fertilizers, herbicides and pesticides.

What we eat today is very different from what our grandparents used to eat. A few years back more vegetables and fruits were used in the daily diet. Due importance was given to the cereals too. But with the changing times our food habits have also changed. In old times there was less use of pesticides and chemical fertilizers as compared to present times.

Today a lot of fast food and processed food has taken place of vegetables and pulses. This is the main reason for nutritional deficiency amongst us today.

The food habits also vary from place to place. Different regions have different food habits and this has an effect on the crops grown there. Cultures also have effect on the food eaten in a region.


For example:

In north, a lot of dairy products are used in cooking the food, in west of our country fishes and coconut are included in the food. So different people from different places and cultures have different food habits.

We all eat food and need it in order to live and work. But there are people who do not get enough food sometimes. This situation can be either because of natural causes or it can be man-made.

The lock of availability of food is called famine.

Sometimes lack of rain causes famine. This situation is called drought. The decrease in supply of water does not let the crops to grow and hence there is shortage of food.

The other reasons can be floods, volcanic eruptions and earthquakes. Sometimes the production of food is less than required.

There can also be shortage of food when the food gets spoiled in a large quantity. This happens when the food is stored improperly. Because of this the food gets wasted.

This causes a lot of diseases and deaths. The diseases caused due to improper or inadequate food are called ma nutrition diseases where the word 'malnutrition' means lack of nutrition. Our body can work properly only if we get proper and sufficient food.

Some of the major malnutrition diseases in the world are:


Name of the disease

Occurs due to deficiency of






Vitamin C        




Vitamin D, calcium or phosphorus



Foods that contain the nutrient

Swollen abdomen and shortness of breath      

Wheat gram, nuts and most of the vegetables.

Swollen abdomen and diarrhea

This has to be carefully treated. You can’t give protein rich diet straightly

Loss of hair and teeth swelling and pain in joints

Citrus fruits, guavas, tomatoes.

Diarrhea, insomnia and memory loss

Whole grains peanuts and lentils.

Skeletal deformation, pain in bones

Fatty fish, cow’s milik egg yolk.


Hunger is something which our body makes us feel when it needs food. We want to eat something when we feel hungry and our body needs energy to do work People fall prey to the above mentioned diseases when they do not get food and some of them even die due to hunger To fight from situations like this the food stored in god owns is used. A go down is like a storehouse where the extra grains and cereals are preserved so that they can be j used when there is not sufficient production of food But a proper care is needed as sometimes a lot of food is; wasted due to improper storage of food.

How do we taste food? When we taste food we get different tastes from different foods. Our tongue helps us to taste the food with the help of our brain. There are different taste buds in our tongue which can detect different tastes. One region of our tongue can taste sour while the other can taste sweet and so on.


Digestion starts from mouth: The role of mouth is not only to take the food inside and chew it but also to digest it. The salivary glands present in mouth start producing saliva when the smell of food starts coming. They produce more saliva when the food is taken inside the mouth. There is also secretion of juices which help the food to break down further. So in this way the saliva starts the, digestion of food from mouth. Sometimes when we eat rice or chapatti, etc., we get a taste of sweetness after chewing them for some time. This is because rice or the chapatti contains starch which is converted to sugars with the action of saliva.

Our body changes the food to glucose which then gets mixed with the bloodstream.

What is glucose?

It i8s an important energy source that is needed by all the organs of our body. It comes from we eat.

Glucose is given to the person who is ill when his body is not in the state to form it. It is given to the patient so as to provide energy to his body.

Plants also need food: Like any other living being, plants also need food. You have already studied in previous classes that plants need water, air and sunlight to prepare their food. This process is known as photosynthesis.



Some of the plants like pitcher plant, Venus fly trap, sundew etc., eat insects and hence are called insectivorous.

Food for animals: All animals need food to survive. There are different types of food that different animals eat.

The types of animals depending on their food are:

  1. Herbivores: These are the animals which eat plants only. For example: cow, goat and horse, etc.
  2. Carnivores: These animals eat other animals such as lion, leopard and eagle, etc.
  3. Omnivores: These animals eat both plants and animals. For example: human beings, bears and rats.

So now you can see, that all the animals have different types of food. Sometimes one animal eats the other and so on. Together they form a chain called food chain.

For example:

  1. Earthworms are eaten by birds which in turn are eaten by snake.
  2. Leaves are eaten by giraffes which are eaten by lion.

Many food chains put together is called food web.

As we can see that growing food is not easy and many people do not get to eat proper amount of food, we should try to minimize the wastage of food. We can do so in these ways:

  • We should buy only those things which we are going to use and those too in required quantity.
  • We should keep the eatables properly so that they do not get spoiled.
  • We should cook the food according to the need.

By following these steps we can minimize the wastage of

Food and we can fight against situation like famine.

Other Topics

Notes - Food
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