Chapter 5 – Food Safety (Class 7)

Chapter 5: Food Safety

Class 7 • Maharashtra Board General Science Mobile-friendly • Neat & Colourful

1) 20 Important Words & Meanings (Meanings in Hindi)

Food spoilageखाना खराब होना — रंग, गंध, स्वाद, बनावट या पोषकता बदल जाना।

Contaminationखाने में गंदगी/जीवाणु/रसायन मिल जाना।

Food wastageखाने का बेवजह फेंकना या गलत तरीके से खराब करना।

Quantitative wastageमात्रा का नुकसान — उत्पादन, भंडारण, परिवहन में।

Qualitative wastageगुणवत्ता का नुकसान — ज़्यादा पकाना, गलत संरक्षण आदि।

Preservationखाने को लंबे समय तक सुरक्षित रखने की विधियाँ।

Protectionखाने को कीटों/सूक्ष्मजीवों से बचाने के उपाय।

Pasteurizationखाना (जैसे दूध) को तय ताप पर गरम करके तुरंत ठंडा करना।

Dehydrationधूप/गर्मी से सुखाकर पानी निकालना।

Irradiationखाद्य को किरणों के संपर्क में लाकर कीट/जीवाणु नष्ट करना।

Smokingधुएँ से खाद्य की सुरक्षा/संरक्षण करना।

Inert gas packingनाइट्रोजन जैसी गैस भरकर फफूँद/कीट का बढ़ना रोकना।

Adulterationखाने में मिलावट — घटिया/हानिकारक पदार्थ मिलाना।

Adulterantमिलावट करने वाला पदार्थ (ईंट-धूल, रंग, चीनी सिरप आदि)।

FSSAIभारत की संस्था जो भोजन की सुरक्षा मानक तय करती है।

FDAसरकारी संस्था — खाद्य और दवाओं का मानकीकरण व निगरानी।

Expiry dateउपयोग की अंतिम तिथि — इसके बाद खाना सुरक्षित नहीं।

Rancidityतेल/वसा का खराब होकर दुर्गंध आना।

Hygieneसफाई व स्वच्छ आदतें — बीमारी से बचाव।

Buffer/Buffetस्व-सेवा पद्धति — जितना चाहिए उतना लेना, बर्बादी कम।

2) Important Notes (Quick Revision)

Balanced diet: All nutrients (carbs, proteins, fats, vitamins, minerals, fibre, water) are essential for growth & health.
Food spoilage indicators: change in colour, odour, texture, taste, quality, nutrient loss. Causes: microbes, insects, moisture, heat, wrong handling, chemical reaction with metals (e.g., acidic foods), poor storage/transport.
Street foods: Always check clean water use, handling hygiene, covered display.
Wastage types: Quantitative (loss of amount: bad storage, transport, over-serving); Qualitative (loss of quality: overcooking, excess preservatives, washing after cutting, mis-handling).
Prevent wastage: Take only what you eat; reuse leftovers safely; buy needed amounts; proper storage; check manufacture & expiry dates; finish served food.
Protection vs Preservation: Protection = prevent spoilage by microbes/pests; Preservation = use methods/agents to keep food safe longer.

Key preservation numbers: Pasteurization of milk ≈ \(80^\circ\text{C}\) for \(15\) minutes, then quick cooling. Safe chill storage ≈ \(5^\circ\text{C}\).

Method	How it helps	Notes / Examples
Freezing / Refrigeration	Slows chemical & microbial reactions.	Domestic refrigerators prolong shelf life.
Dehydration (Drying)	Removes water needed by microbes.	Sun-drying grains, papad, spices.
Boiling	Kills many microbes.	Boil water/milk before use if needed.
Air-tight packing	Limits oxygen & contamination.	Bottles, cans, vacuum packs.
Smoking	Smoke chemicals inhibit microbes.	Traditional method; grains may use fumigants like aluminium phosphide.
Inert gas packing	Displaces air to stop oxidation/mould.	Nitrogen in wafer packets.
Use of insecticides	Controls storage pests.	e.g., Melathion spray on gunny bags (handled by trained personnel only).
Irradiation	Destroys microbes & insects; delays sprouting/ripening.	Onions/potatoes (Lasalgaon), spices (Navi Mumbai).
Natural preservatives	Salt, sugar, oil create hostile environment.	Pickles, jams, murabba, petha.
Chemical preservatives	Inhibit microbial growth.	Acetic acid (vinegar), citric acid, sodium benzoate, nitrate/nitrite salts (jellies, sauces, ready-to-eat).

Institutions: FSSAI under Food Safety and Standardization Act-2006; state FDA monitors standardization & distribution.
Special days: World Food Day — 16 October (food security, avoid wastage).
Adulteration harms: From stomach upset to long-term organ damage and even cancer; always test/avoid suspicious foods.

3) 20 Important “One-Word Answer” Type Questions

Which act created India’s central food safety authority?
Food Safety and Standardization Act-2006.
Name India’s central food safety authority.
FSSAI.
State agency that standardizes food and drugs.
FDA (Food and Drug Administration).
Process of heating milk then rapid cooling.
Pasteurization.
Drying grains in hot sun is called?
Dehydration.
Packing chips with nitrogen is called?
Inert gas packing.
Spoilage by bad smell/taste/colour change is?
Food spoilage.
Mixing harmful/cheap material in food.
Adulteration.
Harmful colour often used to fake turmeric.
Metanil (Metanyl) yellow.
Adulterant found with rava detected by magnet.
Iron filings.
Seeds used to adulterate black pepper.
Papaya seeds.
Natural preservative used in pickles.
Salt / Oil.
Chemical preservative in sauces/jellies.
Sodium benzoate / Acetic acid.
Method using ionizing radiation for safety.
Irradiation.
Temperature often used to keep food safe.
About \(5^\circ\text{C}\) (refrigeration).
Scientist associated with pasteurization.
Louis Pasteur.
Day observed to reduce hunger and wastage.
World Food Day (16 October).
Bad taste from spoiled oils/fats is called?
Rancidity.
Term for preventing microbial growth & pests.
Food protection.
Term for long-term keeping of food safe.
Food preservation.

4) 20 Very Short Answer Questions (1–2 lines)

List two signs of food spoilage.
Off-odour and unusual colour/texture change.
Why do cut fruits turn black?
Enzymatic browning on exposure to air; prevented by lemon (citric acid) or airtight storage.
Name two natural preservatives.
Salt and sugar (also oil).
Give one chemical preservative.
Acetic acid (vinegar) / Sodium benzoate.
What is inert gas packing used for?
To reduce oxidation and fungal/insect growth.
How does refrigeration help?
It slows chemical and microbial reactions.
Why check expiry date?
After expiry the food may be unsafe or ineffective.
What is qualitative wastage?
Loss of quality due to bad methods (overcooking, excess preservatives).
What is quantitative wastage?
Loss of quantity during farming/storage/transport or over-serving.
State one cause of spoilage during transport.
Heat and poor ventilation causing microbial growth.
Name one adulteration test for milk.
Glass slide test for dilution with water.
Which colour indicates turmeric adulteration with synthetic dye?
Persistent red on adding conc. HCl suggests metanil yellow.
Which preservative group is vinegar in?
Chemical preservatives.
Why use airtight containers?
To block moisture/air and prevent contamination.
Name two foods commonly irradiated in Maharashtra.
Onions and potatoes (also spices/condiments).
Why is uncovered street food risky?
Exposed to dust, flies, and contaminated water handling.
Write one way to reduce household food wastage.
Serve only what you can finish; reuse leftovers safely.
Which insects spoil stored grains?
Weevils, beetles, moth larvae (storage pests).
How does smoking help preservation?
Smoke chemicals suppress microbial activity on food.
Who ensures standards on labels?
FSSAI / FDA.

5) 20 Short Answer Questions (2–3 lines)

Differentiate food protection and preservation.
Protection stops microbial/pest attack; preservation uses methods/preservatives to keep food safe for longer.
Explain pasteurization of milk.
Heat to about \(80^\circ\text{C}\) for \(15\) minutes, then cool quickly to stop microbes and extend keeping time.
How does dehydration work?
By removing water, it prevents microbial growth; grains and spices are often sun-dried.
What is inert gas packing and why nitrogen?
Air is replaced with nitrogen to reduce oxidation and mould growth in snacks like wafers.
List two causes of qualitative wastage.
Overcooking and washing vegetables after cutting; both reduce nutrients and quality.
List two causes of quantitative wastage.
Improper storage/transport and over-serving at feasts.
What is rancidity? How to reduce it?
Spoilage of fats/oils causing bad odour; store in airtight opaque containers and keep cool.
Why are chemical preservatives used in sauces/jellies?
They inhibit microbes where water content is high; e.g., sodium benzoate, acetic acid.
How does irradiation extend shelf life?
Destroys microbes/insects and delays sprouting/ripening in produce like onions and potatoes.
Give two safe leftover practices.
Cool quickly, refrigerate at about \(5^\circ\text{C}\); reheat thoroughly before eating.
How to test rava for iron filings?
Pass a magnet; filings (if adulterated) will stick to the magnet.
Name two street-food hygiene checks.
Covered display and use of clean water/utensils (handler hygiene).
Why are labels important?
They show manufacturing/expiry dates and storage instructions to keep food safe.
How do metals spoil acidic foods?
Acid can react with certain metals, affecting taste/safety; use food-grade non-reactive containers.
State two reasons to avoid adulterated foods.
Immediate poisoning/illness and long-term organ damage or cancer risk.
Give two home preservation methods.
Pickling with salt/oil and making jam with high sugar.
Why are wafers puffy packs?
Nitrogen-filled packs cushion and protect wafers and slow oxidative spoilage.
Write two ways to store grains safely.
Dry thoroughly, store in clean airtight bins; keep off the floor, use pest control as needed.
How does buffet service reduce wastage?
People take only what they need, reducing leftovers and plate wastage.
Give two steps to keep fruits fresh after purchase.
Sort/dry if wet; refrigerate suitable fruits and keep ethylene-sensitive ones away from ripe bananas.

6) Textbook Exercise – Perfect Answers

Q1) Complete the statements using the correct option (Irradiation, dehydration, pasteurization, natural, chemical).

(a) Drying grains in hot sun is dehydration.
(b) Heating milk and instantly cooling is pasteurization.
(c) Salt is a natural preservative.
(d) Vinegar is a chemical preservative.

Q2) Answer in your own words.

(a) How is milk pasteurized?
Milk is heated to about \(80^\circ\text{C}\) for \(15\) minutes and then cooled quickly; this kills most microbes and increases keeping time.
(b) Why should we not consume adulterated food?
It may cause poisoning, abdominal problems, long-term organ damage and even cancer; quality and nutrition are also compromised.
(c) What precautions do parents take to keep foodstuffs safe?
Buy fresh quantities, check labels & expiry, store properly (airtight, cool), keep kitchen hygiene, reheat leftovers well, protect from pests.
(d) How does food spoilage occur? List factors.
Due to microbes/insects, heat & humidity, wrong handling, poor storage/transport, chemical reactions with metals (acid/alkali foods), and time.
(e) Which preservation methods would you use?
Refrigeration/freezing, dehydration, airtight packing, pickling (salt/oil), sugar (jam), chemical preservatives where appropriate, irradiation for specific items.

Q3) What shall we do?

(a) Vendors selling uncovered sweets in open places.
Avoid buying; request covering; prefer shops with covered display and proper hygiene.
(b) Pani-puri served with dirty hands.
Do not consume; choose hygienic vendor using clean water, tongs/gloves.
(c) Purchased large quantity of fruits/vegetables.
Sort, wash & dry; refrigerate suitable items; share/exchange; process some (pickle/jam/drying) to avoid spoilage.
(d) Protect from rats, cockroaches, wall-lizards.
Seal containers; keep kitchen clean/dry; fix nets & cracks; use safe pest control; elevate and rotate stock (FIFO).

Q4) Find the odd-man-out.

(a) salt, vinegar, citric acid, sodium benzoate → salt (natural; others are chemical preservatives).
(b) lakhi dal, brick dust, metanil yellow, turmeric powder → turmeric powder (a food; others are adulterants).
(c) banana, apple, guava, almond → almond (a nut; others are fruits).
(d) storing, freezing, settling, drying → settling (not a preservation method here).

Q5) Complete the chart (Foodstuff — Adulterant).

S.No.	Foodstuff	Adulterant
1	Black pepper	Papaya seeds
2	Turmeric powder	Metanil (Metanyl) yellow
3	Rava (semolina)	Iron filings
4	Honey	Sugar syrup / jaggery solution

Q6) Explain why this happens and suggest remedies.

(a) Qualitative wastage of food.
Overcooking/excess preservatives or washing after cutting reduces nutrients and flavour; cook appropriately, use minimal preservatives, wash before cutting.
(b) Cooked rice is underdone.
Too little water or time; add hot water and simmer; next time use ratio about \( \text{rice}:\text{water} = 1:2 \) (as suitable) and cook covered.
(c) Bought wheat is slightly moist.
Moisture can invite mould; sun-dry thoroughly, cool, then store airtight with periodic checks.
(d) Yoghurt too sour/slightly bitter.
Over-fermentation/warm storage; refrigerate promptly after set, use fresh starter, control time/temperature.
(e) Cut fruits turned black.
Enzymatic browning; use lemon (citric acid), keep airtight/refrigerated, cut just before serving.

Q7) Give reasons.

1. Food remains safe at \(5^\circ\text{C}\).
Low temperature slows microbial growth and chemical reactions, extending safe storage time.
2. Nowadays food is served buffet style in large gatherings.
Guests take only what they need, improving variety, portion control and reducing wastage.

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5. Food Safety