NIOS Class 10 Home Science Activity 5.1- Preservation of Food

In this activity, we observe common food items at home, such as milk, rice and oranges, to understand the signs of spoilage and learn why proper storage and preservation of food is necessary.

Food spoilage occurs when food becomes unfit for consumption due to the growth of microorganisms and enzyme activity. When we understand how easily food spoils, we realize why shelf life is important on packed food in activity 5.2 in detail.

Preservation of Food Activity 5.1 Solutions

 

Aim

To observe different food items at home and identify the signs of spoilage

Materials Required

    1.  Milk

    2. Cooked rice

    3. Orange

    4. Clean bowls or plates

    5. Notebook and pen

Procedure

We take three food items commonly used at home: milk, cooked rice and oranges. We keep these food items at room temperature for some time. Then we observe the food items after a few hours or the next day.

After that, we carefully note any changes such as smell, colour, texture or appearance and record our observations in the table.

Observation

Food	Spoilage
Milk	Milk becomes sour, develops a bad smell and may curdle.
Cooked rice	Develops a sour smell and may show sticky texture or fermentation.
Oranges	Develops soft brown spots and may show fungal growth and a bad smell

 

Explanation

Food spoilage occurs mainly due to the action of microorganisms, enzyme and insects. Microorganisms such as bacteria and fungi grow rapidly in warm and m moist conditions.

In milk, bacteria cause souring and curdling. Cooked rice contains moisture, which allows microorganisms to grow quickly, causing fermentation and a bad smell.

Fruits like oranges may develop soft spots or fungal growth due to enzyme activity and microbial attack.

If we use proper storage methods such as refrigeration, drying and the use of preservatives, which actually slow down the spoilage process.

 

Conclusion

We can conclude that food items spoil quickly if they are kept at room temperature for a long time. Spoilage can be identified by changes in smell, colour, and texture. Proper food storage and preservation methods are important to prevent food wastage and keep food safe for consumption.

 

Multiple Choice Questions

Q1. Food spoilage means

(a)       Food becomes tasty

(b)      Food becomes unfit for eating

(c)       Food becomes colourful

(d)      Food becomes dry

Correct answer –(b) – Food becomes unfit for eating

Q2. Which of the following is a sign of food spoilage?

(a)       Pleasant smell

(b)      Increase in size

(c)       Change in colour and bad smell

(d)      Sweet taste

Correct answer – (c) - Change in colour and bad smell

Q3. Milk spoils quickly because it

(a)       Contains less water

(b)      Is kept covered

(c)       Is thick

(d)      Contains more nutrients and moisture

Correct answer – (d) - Contains more nutrients and moisture

Q4. When milk spoils, it

(a)       Becomes sour and curdles

(b)      Becomes sweet

(c)       Becomes solid

(d)      Becomes colourless

Correct answer – (a) - Becomes sour and curdles

Q5. Cooked rice spoils faster due to

(a)       Low temperature

(b)      Dryness

(c)       Presence of moisture and nutrients

(d)      Lake of air

Correct answer – ( c) – Presence of moisture and nutrients

Q6. Spoiled rice usually shows

(a)       Fragrance

(b)      Sour smell and stickiness

(c)       Hardness

(d)      Dryness

Correct answer – (b) – sour smell and stickiness

Q7.  Soft brown spots on oranges indicate

(a)       Freshness

(b)      Ripeness

(c)       Spoilage

(d)      Sweetness

Correct answer – (c ) – spoilage

Q8.  The main cause of food spoilage is

(a)       Sunlight

(b)      Microorganisms

(c)       Wind

(d)      Dust

Correct answer – (b) - microorganisms

Q9. Which condition helps microorganisms grow quickly?

(a)       Warm and moist place

(b)      Cold and dry place

(c)       Dark cupboard

(d)      Airtight jar

Correct answer – (a) warm and moist place

Q10. Food kept at room temperature for a long time

(a)       Remains fresh

(b)      Dries up

(c)       Spoils quickly

(d)      Becomes hard

Correct answer – (c ) – spoils quickly

Q11.  Enzymes present in fruits cause

(a)       Drying

(b)      Hardening

(c)       Ripening and later spoilage

(d)      Freezing

Correct answer – (c ) – ripening and later spoilage

Q12.  Which of the following foods spoils the fastest?

(a)       Sugar

(b)      Pulses

(c)       Rice grains

(d)      Milk

Correct answer – (d ) – milk

Q13.  Fungal growth on food is called

(a)       Dust

(b)      Rust

(c)       Mould

(d)      Stain

Correct answer – (c ) – mould

Q14. Bad smell in food is due to

(a)       Fresh air

(b)      Fermentation by microorganisms

(c)       Sunlight

(d)      Washing

Correct answer – (b) – Fermentation by microorganisms

Q15.  Which of the following can prevent food spoilage?

(a)       Proper storage and preservation

(b)      Keeping food open

(c)       Keeping food in sunlight

(d)      Adding water

Correct answer – (a) – proper storage and preservation

Q16. Fruits and vegetables get spoiled faster when

(a)       Their skin is damaged

(b)      They are kept in fridge

(c)       They are dry

(d)      They are unripe

Correct answer – (a) – their skin is damaged

Q17.  The black or green growth seen on spoiled food is

(a)       Stain

(b)      Dust

(c)       Mould

(d)      Colour

Correct answer- (c ) – mould

Q18.  Which of the following is NOT a cause of food spoilage?

(a)       Microorganisms

(b)      Enzymes

(c)       Insects

(d)      Airtight container

Correct answer – (d) – Airtight container

Q19.  Spoilage of food can be identified by

(a)       Teste only

(b)      Smell, colour and texture

(c)       Colour only

(d)      Size only

Correct answer – (b)- smell, colour and texture

Q20. The activity teaches us mainly about

(a)       Observing signs of food soilage

(b)      Cooking food

(c)       Storing clothes

(d)      Buying food

Correct answer- (a) Observing signs of food soilage

Frequently Asked Questions

    1. What is food spoilage?

Answer – Food spoilage is the process by which food becomes unfit for consumption due to microorganisms, enzyme action or pests.

    2. What are the common signs of food spoilage?

Answer – Bad smell, change in colour, mould growth, fermentation and soft spots on food.

    3.  Why does milk spoil quickly?

Answer – Milk contains moisture and nutrients, which allow bacteria to grow rapidly and cause it to turn sour.

     

    4. How can food spoilage be prevented?

Answer- Food spoilage can be prevented by refrigeration, drying, heating, and using preservatives.

    5. Why is food preservation important?

Answer- Food preservation increases shelf life, prevents wastage and allows foods to be available all the time.

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