Make a table of 10 different food
items including cereals & pulses stored
without spoiling. Explain the method.
applied in each case
Answers
Explanation:
1. Bacteria
They are the most abundant microorganisms found on the earth. They are tiny in size and vary in shape. Some bacteria are useful also. They help to convert milk into curd.
Food SpoilageBacteria growth (Source: femininetouchblog)
2. Protozoa
They are single-celled microorganisms that cause disease like food poisoning etc.
3. Fungi
They are found in damp and warm places and grow on the dead and rotting matter.
Food SpoilageFungi (Source: sciencedaily)
4. Temperature
Temperature is one of the major factors which is responsible for food spoilage.
Signs of food spoilage
Signs of food spoilage include an appearance different from the fresh food, such as a change in color, a change in texture, an unpleasant odor or taste.
Activity I
Aim: To study the growth of fungus.
Materials: Piece of bread
Method: Take a piece of bread. Make it moist and keep it in a warm corner of the room for 3-4 days. Observe it after 3-4 days.
Observation: Presence of greenish patch growing on the bread.
Food Spoilage(Source: i2-prod.mirror)
Food Preservation
Food is valuable. Preserving food can help to avoid wasting of food. Food preservation involves preventing the food from being spoilt. Preservation of food is the process by which food is stored by special methods. Cooked or uncooked food can be preserved in different ways to be used later. Some methods of preservation are:
1. Freezing
Food kept in a refrigerator remains fresh for some days. Germs do not grow easily in cool places. We preserve food items, like milk fruit, vegetables and cooked food by keeping them in a refrigerator.
Food SpoilageMethod of freezing (Source: skinnycentral)
Activity II
Aim: To understand the principle of food preservation.
Materials: Two apples, fridge
Method: Take two apples. Keep one apple in the fridge and one outside for 2-3 days. Record your observation.
Observation: The apple inside the fridge is fresh while the one outside will start decaying.
Food Spoilage(Source: food.onehowto)
2. Boiling
By this method, we can preserve food for a short period of time. Germs in milk are killed by pasteurization. It is done by boiling milk for sometimes and then cooling it quickly.
3. Salting
We can add salt to preserve pickles and fish.
4. Sweetening
Excess sugar in food also acts as a preservative. We store food for a long time in the form of jams, jellies, and murabbas by adding sugar.
5. Dehydration
In this method, the food items are dried in sun to stop the growth of bacteria in them. Certain foods, like raw mangoes, fishes, potato chips and papads are preserved by this method.
Food Spoilage(Source: amazonaws)
6. Canning
In this method, air is removed from food and put in airtight cans so that germs do not grow on them. Food items like vegetables, seafood, dairy products etc. Are preserved through this method.
Food Spoilagecanning
Advantages and Disadvantages
Advantages of food preservation: Germs do not grow easily in preserved food and make it safe to eat. Preservation enables us to enjoy seasonal fruits like strawberries and mangoes even during the offseason.
Disadvantages of food preservation: Excess salt and sugar are used in the preservation of food which is not good for health. Some methods of food preservation may lead to loss of nutrients.