Food Safety Std 7 General Science Lesson 5 question and answers

Std 7, class 7 General science Lesson 5, chapter 5 Food Safety Questions and Answers.


1. Complete the following statements by using the correct option from those given below.

(Irradiation, dehydration, pasteurization, natural, chemical)

(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?

Ans. Pasteurization of milk involves heating the milk at 80o C for 15 minutes and cooling it quickly. This destroys the microbes present in the milk and it keeps for a longer duration.

(b) Why should we not consume adulterated food materials?

Ans. We should not consume adulterated food material because the health of all people is endangered by food adulteration. Different types of adulterants affect our health in different ways. Some adulterants cause abdominal discomfort or poisoning, while some may affect the functioning of some organs if consumed over a long period of time, or even cause cancer.

(c) What precautions do your parents take to keep foodstuffs safe?

Ans.  To keep the food stuff safe my parents do the following steps:

            (a) Buy food stuff from stores that maintain hygiene.

            (b) Checking the expiry date of packed, bottled and canned food before buying.

            (c) Storing dry food items like grains, cereals, pulse, flours etc. in air – tight containers.

            (d) Washing the vegetables and fruits thoroughly and then refrigerating them.

            (e) Discarding the food items that have crossed their expiry date.

            (f) Discarding the food items which are giving foul odour, have become rancid or have black spots on them.

(d) How does food spoilage occur? Which are the various factors spoiling the food?

Ans. Food spoilage occurs if it changes its colour, odour, texture, quality, taste and there is a loss of its nutrient content.

Factors spoiling food are:

(i) Various kinds of changes occur in food materials. For example, fruits turn black or change taste, meat becomes sour or peanuts become rancid. All these changes occur due to factors within the food materials.

(ii) Improper handling, improper storage, improper transportation, etc.

(iii) Some foodstuffs like meat and milk are either acidic or alkaline. They may get spoiled due to chemical reactions on contact with metals.

(iv) Foodstuffs may be spoiled due to contamination by micro-organisms or insects from the surrounding air, water or soil.

(e) Which methods of food preservation would you use?

Ans. I would use the following methods of food preservation:

freezing, drying, boiling, air-tight packing, making pickles and jams.

3. What shall we do?

(a) There are vendors selling uncovered sweetmeats in open places in the market.

Ans. We should not buy from such vendors. We should also politely request them to sell the foodstuff covered as well as explain to them the benefit of covering the food. Thereby, increasing sale and profits.

(b) A ‘pani-puriwalla’ is serving the pani puri with dirty hands.

We should not consume from such a person. We should also politely request him to maintain hygiene. As well as explain to him the benefits serving food with clean hands which will lead to increasing sale and profits.

(c) We have purchased a large quantity of fruits and vegetables.

Ans. We should refrigerate as much as we can. The balance should be made into jams, pickles, juices, etc.

(d) We need to protect foodstuffs from pests like rats, cockroaches, wall- -lizards, etc.

Ans.  In order to protect the food stuff from pests like rats, cockroaches, wall – lizard, first of all we should keep our house clean, especially the kitchen. We should also store the dry food stuff in air tight containers.

4. Find the odd-man-out.

(a) salt, vinegar, citric acid, sodium benzoate

Ans.  Salt is the odd-man-out because it is a natural preservative while the others are chemical preservatives.

(b) lakhi dal, brick dust, metanyl yellow, turmeric powder

Ans.  Tumeric powder is the odd-man-out because it is a spice while others are adulterants.

(c) banana, apple, guava, almond

Ans.  Almond is the odd-man-out because it is a dry fruit while all others are fresh fruits.

(d) storing, freezing, settling, drying

Ans. Settling is the odd-man-out because it is a procedure of separation while the others are methods of preservation.

5. Complete the chart below:

Sr. No. Foodstuff Adulterant
1 Turmeric powder Metanyl yellow
2 Black pepper Papaya seeds
3 Rava Iron filings
4 Honey Sugar syrup

6. Explain why this happens and suggest possible remedies.

(a) Qualitative wastage of food.

Using wrong methods of protecting food, excessive use of food preservatives, over-cooking, washing the vegetables after cutting them, mis-handling of fruits like grapes and mangoes, mis-calculation of the time required to transport food from producers to consumers, are some of the causes of qualitative wastage of food.

Remedies for reducing qualitative wastage of food are banning the use of food preservatives, accurately calculating the time required for transportation, taking care while handling food stuffs, washing fruits and vegetables before cutting them etc.

(b) The cooked rice is underdone.

Ans. If the cooked rice is undone then it can be used to prepare food items which require it to be cooked again e.g. fried rice, kichadi. kheer, firni, etc.

(c) The wheat that was bought is a bit moist.

Ans. Wheat has to be dry before it is given to the mill to make into flour, therefore if wheat that was bought is a bit moist then, thoroughly dry it in the sun because damp wheat can be infested with micro-organisms which can be very harmful if consumed.

(d) The taste of yoghurt is too sour/slightly bitter.

Ans. Such yogurt should be made into lassi or could be used to prepare dahi-curry.

(e) Cut fruits have turned black.

Ans. Cut fruits turn black due to oxidation of nutrients, such fruits should be rubbed with lemon to stop the process of oxidation.

7. Give reasons.

1. Food remains safe at 5o Celsius.

Ans. Biological and chemical reactions in food materials are slowed down at low temperature. As a result, food remains in good condition for a longer duration.

2. Nowadays, food is served buffet style during large gatherings.

Ans. Nowadays, food is served buffet style during large gatherings to avoid wastage of food as people can serve for themselves as much as they want.

Project :

1. Go to your kitchen and take notes about the food safety measures and the food wastage you see there.

2. In a science exhibition demonstrate the various methods of detecting food adulteration.

Let’s recall.

Complete the following chart with the correct information.

Sr. No. Food / Source Nutrients obtained Function in body
1 Jowar, wheat, millet (bajra), rice Carbohydrates Energy giving
2 Beans and pulses Proteins and fibres Body Building
3 Oil, ghee, etc Fats Energy giving food
4 Fruits and vegetables Vitamins & minerals Protection against diseases

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