NCERT Solutions for Class 5 The World Around Us Chapter 3 the Mystery of Food (PDF) – 2027

Tiny living things called microbes grew on the uttapam and spoiled it. The tiffin box lay in school for three days. The soft, moist uttapam gave the microbes moisture, air and warmth, so they multiplied. The coloured patches were mould — a colony of thousands of microbes — and the microbes also made the food smell foul.

No. Microbes are much smaller than lice. A louse can be seen with our eyes, but a single microbe cannot. We need an instrument called a microscope to see microbes. Microbes are found everywhere — in soil, water, the air, plants, animals and even inside us.

Yes. An upset stomach is usually caused by harmful microbes that enter the body with stale or spoiled food, uncovered cut fruit, unsafe water or unwashed hands. Eating too fast or too much can also cause indigestion.

Sample answer: “Yes. Once I ate cut fruit that had been lying open in the sun at a fair. That night my stomach hurt. I think microbes had grown on that fruit.”

Eating spoiled food can make a person ill. The harmful microbes in it can cause stomach pain, vomiting, loose motions (diarrhoea), weakness and sometimes fever. The person should tell an elder at once, sip plenty of safe water or ORS, and see a doctor if the problem is severe.

“When my stomach was upset, I rested and did not eat oily food. Amma gave me boiled water and ORS in small sips, and later khichdi and curd. By the next day I felt better.” (If the problem does not get better, a doctor must be consulted.)

Food spoils fast when microbes can grow on it easily, and lasts long when something stops them. The bread on the balcony was soft, moist and open to air and warmth, so mould grew on it in two days. Paati’s pickle was covered with oil, which kept the air out, so it was still good after two months.

Food gets spoiled because microbes grow on it and change its colour, smell and taste. Microbes grow fastest when the food has moisture, is open to air, is kept warm and is left for a long time. Then the food is no longer safe to eat.

Microbes need three things to grow: moisture, air and the right temperature. If we take away even one of these three, they cannot grow — we can stop them in their tracks. That is Finding #2 in Disha’s notebook.

We save food from spoilage by keeping microbes away from it, or by taking away what they need to grow. The main ways are: (1) drying in the Sun, (2) pickling with salt and oil, (3) keeping food cold in a fridge, (4) using salt, sugar and spices, and (5) sealing food in airtight cans and packets.

Amma answered, “To make chilli powder. This should last us for the entire year!” Drying in the Sun removes the moisture from the chillies. Without moisture, microbes cannot grow, so the dried chillies and the powder made from them do not spoil (Finding #3).

Papad, badi (vadi), sevai, raw mango slices (for amchur), tea leaves, red chillies, turmeric, coriander seeds, aam papad, raisins, dried fish and sun-dried tomatoes are dried so that they remain unspoilt throughout the year. Drying removes their moisture, so microbes cannot grow on them.

Six items to write in the boxes: mango pickle, aam papad, amchur (dry mango powder), mango murabba, mango jam or squash, and canned mango pulp or juice.

The tomato slices slowly lose their water. They shrink, become wrinkled and leathery, and turn a darker red. After a few days they become dry, light and hard. This happens because the Sun’s heat evaporates the water in the slices.

Yes. Tomatoes can be preserved by sun-drying the slices, by keeping them in a fridge, or by making them into purée, sauce, ketchup or pickle and sealing it in clean, airtight bottles or cans. Each way takes away the moisture, air or warmth that microbes need.

Paati explained, “Oil stops air from getting in. That keeps the pickles safe!” Oil is lighter than water, so it floats on top and covers the pickle. Without air, microbes cannot grow, so the pickle stays good for months.

Finding #4: Oil keeps out air and stops the growth of microbes.

Without oil, air would reach the pickle, microbes would grow on it, and it would spoil in a few days or weeks instead of lasting for months.

Butter still has water in it, but ghee does not. Ghee is made by heating butter until the water in it separates and evaporates. Microbes need moisture, so they can grow in butter — that is why butter is kept cold in a fridge. Ghee has almost no water, so it stays good at room temperature.

“My grandmother makes badis every year. She grinds soaked urad dal into a thick paste, puts small lumps of it on a clean cloth and dries them in hot sunlight for about four days. Then she stores the hard, dry badis in a tin with a tight lid. They last the whole year because drying has removed their moisture.”

Idlis are made from a batter of rice and urad dal. The rice and dal are soaked, ground and mixed with a little salt. The batter is left overnight in a warm place, where it rises and becomes light and fluffy. Then it is poured into idli moulds and steamed.

Yes — microbes. Microbes present in the air get into the batter and grow in it overnight. As they grow they give off a gas. The gas makes tiny bubbles all through the batter, and those bubbles make the idli soft and fluffy.

Finding #7: Microbes in the air help make idli batter rise.

“Yes. Once I ate too many puris at a wedding and my stomach felt heavy. My mother gave me a little roasted ajwain with a pinch of black salt and warm water, and later a glass of buttermilk. I ate nothing heavy that night, and by morning I felt fine.”

Yes. Curd, or buttermilk made from it, is often given for an upset stomach. Curd has small microbes in it. These join the good microbes in our stomach and help in digestion. If the problem is severe, we must consult a doctor and take the medicines advised.

Elders check fruits and vegetables carefully before buying them. They look for a bright colour with no spots, cuts, holes or mould; press gently to feel that they are firm; smell them; check that the stalk and leaves are fresh; and buy local, seasonal produce — only as much as the family will eat.

Sample answer — written as Disha would:

“In my region, amla and carrots come in winter, mango and jamun come in summer, and bhutta (corn) comes in the rainy season.”

Inside the mouth, food is cut, torn, crushed and ground by the teeth, mixed by the tongue, wetted by saliva, and turned into a soft mush that can be swallowed easily. Digestion actually starts right there in the mouth.

We use the incisors (front teeth) to cut, the canines to tear, the premolars to crush and the molars to grind the food. Different types of teeth have different uses (Finding #11).

Yes. The longer we chew, the more saliva comes out. Chewing properly breaks the food into small pieces and releases saliva, which wets the food and helps in digestion (Finding #10).

Eat slowly, take small mouthfuls, chew properly, and never talk, laugh, run or lie down with food in your mouth.

Finding #13: I must eat my food slowly to avoid choking on it.

Because microbes can grow easily on some foods and not on others. A food spoils fast if it has plenty of moisture, is open to the air and is kept warm. A food lasts for weeks if it is dry, salty, sugary, oily, sealed or cold — because then the microbes cannot get what they need.

Five food items: (1) theplas or khakhras, (2) roasted chana and peanuts, (3) chikki or til-gur ladoos, (4) whole fruits such as bananas and oranges, (5) a sealed packet of biscuits.

How I will keep them from spoiling: pack them in clean, dry, airtight boxes; keep the bag out of the sun; keep the fruits whole, not cut; and not carry curd, gravy or cooked rice.

Without food preservation, food would have to be eaten as soon as it is cooked or harvested, and the rest would spoil and be wasted. There would be no pickle, papad, ghee or chilli powder; seasonal foods would be found only in their season; we could not carry food on journeys; and a flood or drought would quickly leave people hungry.

The filled table: