Question Answers For All Chapters – General Science Class 7
Food Safety
Exercise
1. Complete the following statements using the correct options.
(a) Drying the food grains from farms under the hot sun is called Dehydration.
(b) Materials like milk are instantly cooled after heating up to a certain high temperature. This method of food preservation is called Pasteurization.
(c) Salt is a Natural type of food preservative.
(d) Vinegar is a Chemical type of food preservative.
2. Answer the following questions in your own words.
(a) How is milk pasteurized?
→ Milk is heated to 80°C for 15 minutes and then cooled quickly. This process kills harmful bacteria and makes the milk safe for longer use.
(b) Why should we not consume adulterated food materials?
→ Adulterated food contains harmful chemicals or substances that can cause illness, food poisoning, and even long-term diseases like cancer.
(c) What precautions do your parents take to keep foodstuffs safe?
→ Food is stored properly in airtight containers, refrigerators, and dry places. They also check expiry dates and wash fruits and vegetables before eating.
(d) How does food spoilage occur? Which are the various factors spoiling the food?
→ Food spoils due to bacteria, fungi, air, moisture, temperature changes, and improper storage. It can also spoil due to chemical reactions or contamination.
(e) Which methods of food preservation would you use?
→ I would use freezing, drying, airtight packing, adding preservatives (salt, sugar, vinegar), and pasteurization to keep food fresh.
3. What shall we do ?
(a) There are vendors selling uncovered sweetmeats in open places in the market.
→ We should not buy such food because it may be contaminated with dust, bacteria, and insects.
(b) A ‘pani-puriwalla’ is serving the pani puri with dirty hands.
→ We should avoid eating there and inform the vendor about hygiene.
(c) We have purchased a large quantity of fruits and vegetables.
→ We should store them properly in the refrigerator or a cool, dry place to prevent spoilage.
(d) We need to protect foodstuffs from pests like rats, cockroaches, and wall lizards.
→ We should keep food in sealed containers, clean storage areas, and use natural repellents.
4. Find the odd man out.
(a) Salt, vinegar, citric acid, sodium benzoate
→ Sodium benzoate (it is a chemical preservative, while others are natural preservatives).
(b) Lakhi dal, brick dust, metanyl yellow, turmeric powder
→ Turmeric powder (it is natural, while others are adulterants).
(c) Banana, apple, guava, almond
→ Almond (it is a dry fruit, while others are fresh fruits).
(d) Storing, freezing, settling, drying
→ Settling (it is not a food preservation method, while others are).
5. Complete the chart below.
S.No. | Foodstuff | Adulterant |
---|---|---|
1. | Turmeric | Metanyl yellow |
2. | Black pepper | Dried papaya seeds |
3. | Rava (Semolina) | Iron filings |
4. | Honey | Sugar syrup |
6. Explain why this happens and suggest possible remedies.
(a) Qualitative wastage of food.
→ Food gets wasted due to overcooking, excessive use of preservatives, or improper storage.
Remedy: Use proper cooking and storage methods.
(b) The cooked rice is underdone.
→ This happens due to insufficient water or low cooking temperature.
Remedy: Add hot water and continue cooking for a few more minutes.
(c) The wheat that was bought is a bit moist.
→ Moist wheat can lead to fungal growth or spoilage.
Remedy: Sun-dry the wheat properly before storing it in airtight containers.
(d) The taste of yoghurt is too sour/slightly bitter.
→ This happens when yogurt is kept for too long or fermented too much.
Remedy: Store yogurt in a cool place and consume it fresh.
(e) Cut fruits have turned black.
→ This happens due to oxidation (when fruit reacts with air).
Remedy: Apply lemon juice to prevent darkening and eat fruits quickly.
7. Give reasons.
1. Food remains safe at 5°C.
→ At low temperatures, bacteria and fungi grow slowly, keeping food fresh for longer.
2. Nowadays, food is served buffet-style during large gatherings.
→ Buffet serving reduces food wastage and allows people to take only as much as they want.
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