Kerala Syllabus Class 7 Basic Science: Chapter 10 Safe Food - Questions and Answers


Questions and Answers for Class 7 Basic Science (English Medium) സുരക്ഷിത ഭക്ഷണം | Text Books Solution Basic Science (English Medium) Chapter 10 Safe Food - Teaching Manual | Teachers Handbook

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ഈ ബ്ലോഗ് അഡ്‌മിൻറ രേഖാമൂലമുള്ള അനുമതിയില്ലാതെ ഈ ബ്ലോഗിൽ നൽകിയിരിക്കുന്ന ചോദ്യോത്തരങ്ങൾ, ഇതേരീതിയിലോ പി.ഡി.എഫ് രൂപത്തിലോ, മറ്റേതെങ്കിലും ഡിജിറ്റലോ, പ്രിന്റഡ് ഉൾപ്പെടെയുള്ള ഏതെങ്കിലും രൂപങ്ങളിലേക്കോ മാറ്റി മറ്റൊരു വെബ്സൈറ്റിലോ, ബ്ലോഗിലോ, യുട്യൂബ്, സോഷ്യൽ മീഡിയാ ഗ്രൂപ്പുകളിലോ ഉൾപ്പെടെ ഒരിടത്തും പ്രചരിപ്പിക്കാൻ പാടില്ലാത്തതാകുന്നു.

Std 7: Basic Science Chapter 10: Safe Food - Questions and Answers

♦ Why do we eat food? Discuss and note your opinions in the Science Diary.
• For healthy growth
• For energy to work
• For physical activity

♦ What are the factors to be considered from the selection of food items to its consumption to get safe food? Write them down.
• Selection of food items
• Cleaning and cutting for cooking.
• Careful cooking
• Storage of cooked items 
• Safe serving
• Consumption of food

♦ What are the precautionary measures to be taken while selecting fish for cooking?
To choose To avoid
• When the finger pressed over the fish is released, the depressed part on the flesh restores its shape• The depression on the fish caused by pressing it with a finger remains.
• Slightly wet and shiny outer skin• Flesh gets detached from the bone
• Shiny and pinkish gills• Slightly greenish or ash-coloured gills
• Intact eyes with normal colour • Sunken eyes
• No foul smell• Foul smell
♦ What factors are to be considered while selecting milk and milk products from shops? Examine the given statements and put (✔) mark in the appropriate boxes. 
• Milk packet with a logo (✔)
• Discoloured milk (X)
• Unpacked milk and milk products (X)
• Date of packing and expiry printed on the packet (✔)
• Quality of the source (✔)
• Packed and sealed cheese and paneer (✔)

♦ Don’t you buy fruits and vegetables from shops? What factors are to be considered while selecting them? Complete the table.
To be selected To be avoid
• Undamaged outer skin
• Fresh and vibrant
• Organic		• Damaged skin
• Signs of Decay
• Unusual or unpleasant smell
♦ What factors are the measures to be taken care of while choosing packed food items?
• Name of the food item
• List of ingredients
• Information regarding nutrients
• Calorific value
• Vegetarian/non-vegetarian symbols
• Quantity, weight
• Date of manufacture, date of expiry
• Place of production, address of producer
• Added preservatives
• Colouring materials used
• License number and fssai logo
• Method of use

♦ Why is Rhodomin B added to jaggery?
To colour jaggery

♦ What is the harm in adding Rhodomin B to jaggery?
The presence of even a minute amount of Rhodomin B in the body can cause fatal diseases like cancer.

♦ What is Adulteration?
Addition of similar, cheap and poor quality substances to food items is called adulteration. Selling food items after the removal of its quality components and unauthorised addition of colours to food items to give the appearance of quality can also be branded as adulteration.

♦ How can detect adulteration in Honey?
Dip a cottonwick in honey and light it. If it burns well, honey is not adulterated. If the lighted wick burns with a crackling sound, the honey is adulterated. This sound is due to the presence of water in the sugar or jaggery solution added to honey. When pure honey is poured into water,  it settles down. If the honey is adulterated, it immediately dissolves in water. 

♦ How can detect adulteration in Turmeric?
Take water in a glass tumbler and sprinkle a pinch of turmeric powder into it. Colour will spread to the bottom if it is adulterated with synthetic dye. If not adulterated, turmeric powder will settle down at the bottom without the colour spreading.
♦ How can detect adulteration in Coconut Oil?
Fill half of a glass tumbler with coconut oil,  keep it in the freezer for 30 minutes and observe it. If the coconut oil is pure, it would have frozen completely. If any other oil had been added to coconut oil, the adulterant oil will float above the coconut oil in the liquid state itself.

♦ How can detect adulteration in Asafoetida?
Take a piece of asafoetida in a spoon and burn it. If it does not burn like camphor, it may be assumed that it is adulterated.

♦ What could be the reason for rice stored in a jar not getting spoiled for a long time and cooked rice getting spoiled after a day?
Spoilage of food items is mainly due to the decomposition action by microorganisms like bacteria and fungus. Micro-organisms become inactive at very high and very low temperatures. Moreover, micro-organisms cannot be active in the absence of moisture. They cannot act on food items which are packed airtight.

♦ Complete the table 
Food Item Method of reservation Reason for Non-spoilage
• Chilli• Dried and stored

• Micro-organisms cannot act in the absence of moisture

• Cherry• In sugar solution

• Micro-organisms get destroyed

• Gooseberry• In salt solution

• Micro-organisms get destroyed

• Pineapple• Jam/salt solution

• Micro-organisms get destroyed

• Chips• Air-tight container

• Micro-organisms cannot act in the absence of moisture

• Drinks• Refrigerate

• Micro-organisms cannot be active at very low temperatures.

• Vegetables• Refrigerate

• Micro-organisms cannot be active at very low temperatures.

♦ Find out more examples of food items which are preserved under each method and expand the table.
Dried and stored Preserved in salt solutionPreserved in sugar solutionPreserved in low-temperature Preserved in airtight container
• Rice
• Chilly
• Chickpea 		• Gooseberry
• Mango
• Lemon		• Cherry
• Pineapple
• Papaya		• Milk
• Vegetables
• Fruits		• Biscuit
• Chips
• Cashew nut
♦ Micro organisms cannot survive in sugar and salt solutions. Why is it so?  
Water from food items preserved in salt solution moves into the salt solution. Salt absorbs water not only from the food items but also from the cells of the micro organisms present in them. Micro organisms get destroyed when their cells lose water. The same thing happens when food items are preserved in sugar solution.

♦ How Jackfruit Jam is made?
Jam is an example for the preservation of food items in sugar. Grind one kilogram of fully ripened jackfruit. Cook until it thickens. Add 500 g of sugar to it and stir well for 10 minutes. Allow it to cool for some time and add a spoonful of lemon juice. After it has cooled down, transfer it into a clean and dry airtight container.

♦ What is Pasteurisation?
Pasteurisation is a method to prevent spoilage of milk. Heat milk to 70°C for 30 seconds and cool it to 10°C immediately. This sudden temperature difference leads to the rupturing of the cell membrane of the micro organisms. As a result, they get destroyed. This process was invented by a French Scientist, Louis Pasteur. Hence, this process is named as pasteurisation. Wine and fruit juices are also preserved by pasteurisation.

♦ Why the food items kept in the refrigerator don’t get spoiled?
The food items are kept in refrigerator to prevent spoilage. Micro organisms cannot be active at very low temperature. That is why food items don’t get spoiled.

♦ What will happen to food items when they are taken out of the refrigerator? 
Micro organisms will start functioning and the food will be spoiled.
Let’s Assess

1. Which adulterant can probably be added to pepper?
a.  Green gram
b. Tamarind seed
c. Papaya seed
d. Bengal gram
Answer: c. Papaya seed

2.  Can the ice cubes used in fish markets be used to prepare cool drinks? Why?
No, while making ice, a chemical substance called Ammonium Chloride is added for the quick condensation of water, to prevent melting and to maintain low temperature. Ammonium Chloride is harmful to our body. 

3.  What are the things to be taken care of while you purchase fruits from shops?
• Undamaged outer skin
• Fresh and vibrant
• Organic

4. Milk, tomato, fish, cucumber, lady’s finger and meat are to be kept in the refrigerator. Out of these,
• Which are to be kept in freezer?
Milk, fish, meat

• Which are to be stored in compartments other than the freezer?
tomato, cucumber, lady’s finger 




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