MAHARASHTRA STATE BOARD
Standard 7 Science – Chapter 5: Food Safety
Detailed Notes | Definitions | Examples | Exam Preparation
Easy English Study Material for Students
Welcome to the detailed study notes for Standard 5 Science, Chapter 5, Food Safety. Learn about food spoilage, food wastage, food protection, food preservation, food adulteration and the importance of safe food. These notes also include important definitions, examples, revision points and practice questions.
Contents
1. Food and Nutrients
Food is essential for the proper growth and functioning of our body. We obtain nutrients from food materials such as cereals, pulses, vegetables, fruits, milk and other food products.
| Food component | Examples | Main function |
|---|---|---|
| Carbohydrates | Rice, wheat, jowar, bajra | Provide energy. |
| Proteins | Beans, pulses | Help in growth and repair of the body. |
| Fats | Oil, ghee | Provide energy and support body functions. |
| Vitamins and minerals | Fruits and vegetables | Help maintain good health. |
| Fibre and water | Vegetables, fruits and drinking water | Support normal body functions. |
Food should be clean, fresh and suitable for consumption. Spoiled or contaminated food may cause illness.
2. Food Spoilage
Signs of food spoilage
- A change in colour.
- An unpleasant or foul smell.
- A change in texture.
- An undesirable change in taste.
- A decrease in food quality or nutrient content.
- Visible mould or other signs of deterioration.
Factors responsible for food spoilage
- Improper handling: Food may be damaged when it is not handled carefully.
- Improper storage: Keeping food in damp or unsuitable conditions may lead to spoilage.
- Overcooking: Excessive cooking may reduce food quality and nutritional value.
- Transportation: Improper transportation or delays can damage food.
- Chemical changes: Chemical reactions may change the quality of certain foods. Meat and milk may undergo changes when they come into contact with certain metals.
- Microorganisms: Microorganisms from the surrounding air, water or soil may contaminate food and cause spoilage.
- Insects and pests: Insects may damage food grains and stored food products.
Examples of food spoilage
- Fruits or their skins turning black.
- Food developing a foul smell.
- Meat becoming sour.
- Peanuts becoming rancid.
- Food developing mould during unsuitable storage.
3. Food Wastage
Food wastage is the loss of food or a reduction in its quality at different stages, from production to consumption. Preventing food wastage is important because many people do not get enough food.
A. Quantitative Food Wastage
Causes and examples:
- Wrong methods of farming, such as hand sowing of seeds.
- Inadequate threshing of food grains.
- Improper storage of harvested food grains.
- Wrong methods of food distribution.
- Serving too much food to guests at feasts and banquets.
Example: If food grains are lost during storage, the total quantity of food available becomes less.
B. Qualitative Food Wastage
Causes and examples:
- Using unsuitable methods to protect food.
- Excessive use of food preservatives.
- Overcooking food.
- Washing vegetables after cutting them.
- Mishandling fruits such as grapes and mangoes.
- Incorrectly estimating the time required to transport food from producers to consumers.
Difference Between Quantitative and Qualitative Food Wastage
| Quantitative food wastage | Qualitative food wastage |
|---|---|
| Loss of the quantity of food. | Reduction in the quality of food. |
| Improper storage may cause grains to be lost. | Overcooking may reduce the quality of food. |
| The amount of food decreases. | The quality or nutritional value decreases. |
4. Prevention of Food Wastage
We can reduce food wastage by following these practices:
- Serve yourself only as much food as you can eat.
- Avoid overcooking food.
- Do not throw away leftover food unnecessarily. Reuse it appropriately and safely.
- Buy only the quantities of grains, vegetables, fruits and milk that you need.
- Store grains and perishable foods using suitable methods.
- Check the expiry date of bottled, canned and packaged food.
- Eat all the food that you have served yourself.
5. Food Protection
Food protection helps prevent food from being damaged by microorganisms and pests. Food should be handled carefully, stored properly and protected from contamination.
6. Food Preservation
Importance of food preservation
- Helps food remain in good condition for a longer time.
- Reduces food spoilage and wastage.
- Helps protect food quality.
- Makes certain foods available for later use.
Food Protection and Food Preservation: Difference
| Food protection | Food preservation |
|---|---|
| Prevents spoilage caused by microbial growth and pest infestation. | Uses suitable methods and preservatives to prevent spoilage for a longer period. |
| Focuses on protecting food against spoilage and pests. | Focuses on extending the period for which food can be stored. |
7. Methods of Food Preservation
1. Freezing
How it works:
- Low temperature slows down changes in food.
- Food remains in good condition for a longer duration.
- Refrigerators and freezers are used to store suitable food items.
Examples: Frozen peas and frozen vegetables.
2. Use of Inert Gas
Nitrogen gas is filled into airtight packets of potato wafers and other food products. This helps prevent the growth of fungus and insects in the packaged products.
Example: Packets of potato wafers.
3. Smoking
Smoking is a food-preservation method discussed in the chapter. The chemicals used in pest control or food treatment must not be handled or applied to food without approved professional guidance.
4. Control of Insects in Stored Food
Insects can damage stored food grains. The chapter discusses insecticides in connection with protecting stored grains.
5. Irradiation
Types of radiation mentioned:
- High-energy electrons.
- X-rays.
- Gamma rays emitted by radioactive isotopes.
Uses and benefits:
- Helps destroy microorganisms and insects.
- Helps increase the shelf life of fruits by slowing ripening.
- Slows sprouting in potatoes and onions.
- Helps preserve selected food products for longer storage.
Examples from Maharashtra: Irradiation facilities are mentioned at Lasalgaon for onions and potatoes and at Navi Mumbai for spices and condiments.
6. Natural Preservatives
| Natural preservative | Food examples |
|---|---|
| Salt | Pickles and other preserved foods. |
| Sugar | Jams, murabba and petha. |
| Oil | Pickles. |
7. Chemical Preservatives
Examples:
- Acetic acid (vinegar).
- Citric acid.
- Sodium benzoate.
- Some nitrate and nitrite salts.
These substances are used in certain food products, such as sauces, jellies, jams, packaged ready-to-cook vegetables and ready-to-eat foods. Only permitted preservatives should be used in approved quantities.
8. Pasteurisation
Steps:
- Heat the milk to a specified temperature.
- Maintain the temperature for a specified period.
- Cool the milk quickly after heating.
The chapter gives an example of heating milk at 80°C for 15 minutes, followed by quick cooling.
Scientist: Louis Pasteur developed the technique associated with preserving food quality by heating to prevent microbial growth.
9. Dehydration
Removing moisture helps reduce conditions that support the growth of many microorganisms and helps food remain suitable for storage.
Example: Drying food grains in the hot sun after harvesting.
10. Other Storage Methods
The chapter also mentions the following methods:
- Drying: Removes moisture from food.
- Boiling: Heating food or liquids can destroy many microorganisms, depending on the conditions.
- Airtight packing: Helps protect food from exposure to the surrounding environment.
8. Food Adulteration
Examples of food adulteration
| Food item | Adulterant or example |
|---|---|
| Milk | Water or urea. |
| Red chilli powder | Brick dust. |
| Turmeric powder | Metanil yellow. |
| Rava (semolina) | Fine iron filings. |
| Food grains | Stones or sand. |
| Other food materials | Sawdust or other inferior substances. |
The chapter also discusses removing fat from milk and removing essence from spices such as cloves or cardamom.
Harmful Effects of Adulterated Food
- It may cause abdominal discomfort.
- It may cause food poisoning.
- Harmful substances may affect the normal functioning of body organs.
- Exposure to certain harmful chemicals may increase the risk of serious illnesses, including cancer.
Why should we avoid adulterated food?
We should avoid adulterated food because it may contain inferior, inedible or harmful substances that can damage our health.
9. Tests for Detecting Food Adulteration
| Food item | Adulterant | Observation described |
|---|---|---|
| Red chilli powder | Brick dust | A red layer may settle at the bottom when the sample is mixed with water and left undisturbed. |
| Turmeric powder | Metanil yellow | The chapter describes a colour reaction using concentrated hydrochloric acid. |
| Rava | Fine iron filings | Iron filings can be attracted by a magnet. |
10. Food Safety Institutions
Food and Drug Administration (FDA)
The chapter describes the Food and Drug Administration as a government organisation that controls the production and distribution of food and drugs through standardisation.
Food Safety and Standards Authority of India (FSSAI)
Full form: Food Safety and Standards Authority of India.
The FSSAI was established under the Food Safety and Standards Act, 2006. It is associated with food safety and food standards in India.
Official website: www.fssai.gov.in
11. Important Definitions for Exams
1. Food Spoilage
Food spoilage is the process in which food undergoes undesirable changes in colour, odour, texture, quality and taste, and may lose nutrient content.
2. Quantitative Food Wastage
Quantitative food wastage is the loss of the actual quantity of food.
3. Qualitative Food Wastage
Qualitative food wastage is the reduction in the quality or nutritional value of food.
4. Food Protection
Food protection is the prevention of food spoilage caused by microbial growth and infestation by pests.
5. Food Preservation
Food preservation is the use of suitable preservatives and methods to prevent food spoilage for a longer period.
6. Irradiation
Irradiation is the exposure of food to ionizing radiation to destroy certain microorganisms and insects and help extend shelf life.
7. Pasteurisation
Pasteurisation is the heating of milk or similar food to a specified temperature for a specified time, followed by rapid cooling, to destroy microorganisms.
8. Dehydration
Dehydration is the removal of water from food by drying.
9. Food Adulteration
Food adulteration is the removal of important components from food or the addition of inferior, inedible or harmful substances.
10. Natural Preservatives
Natural preservatives are naturally available substances, such as salt, sugar and oil, used to preserve food.
11. Chemical Preservatives
Chemical preservatives are substances used to prevent or slow food spoilage.
12. Inert Gas Packing
Inert gas packing is a method in which an inert gas, such as nitrogen, is used in airtight food packets to help protect the contents.
12. Important Exam Questions and Answers
Q1. How does food spoilage occur?
Answer: Food spoilage occurs when food undergoes undesirable changes in colour, odour, texture, quality and taste and may lose nutrient content. It may result from improper handling, unsuitable storage, transportation, chemical changes, microorganisms and insects.
Q2. What are the causes of food spoilage?
Answer: The causes include improper handling, improper storage, overcooking, transportation problems, chemical reactions and contamination by microorganisms or insects from the surrounding air, water or soil.
Q3. How is milk pasteurised?
Answer: Milk is heated to a specified temperature for a specified time and then cooled quickly. This destroys many microorganisms and helps milk remain suitable for storage for a longer duration.
Q4. Why should we not consume adulterated food?
Answer: Adulterated food may contain inferior, inedible or harmful substances. It may cause abdominal discomfort, food poisoning and other harmful effects on health.
Q5. What precautions help keep food safe?
Answer: We should handle food carefully, store it properly, keep it protected from contamination, buy only the quantity required, check expiry dates and avoid eating food that is spoiled or unsafe.
Q6. What methods are used for food preservation?
Answer: Methods discussed in the chapter include freezing, drying, boiling, airtight packing, use of inert gas, irradiation, natural and chemical preservatives, and pasteurisation.
Q7. What is the difference between quantitative and qualitative food wastage?
Answer: Quantitative food wastage means a loss in the quantity of food, whereas qualitative food wastage means a reduction in its quality or nutritional value.
Q8. What are natural preservatives? Give examples.
Answer: Natural preservatives are naturally available substances used to preserve food. Examples include salt, sugar and oil.
Q9. What is irradiation?
Answer: Irradiation is a method in which food is exposed to ionizing radiation to destroy certain microorganisms and insects and help extend its storage life.
Q10. What is the role of FSSAI?
Answer: The Food Safety and Standards Authority of India is associated with food safety and food standards in India. It was established under the Food Safety and Standards Act, 2006.
13. MCQ Practice Test
Select the correct option and then check the answer key below.
1. Which type of food wastage means a loss in the quantity of food?
A. Qualitative
B. Quantitative
C. Chemical
D. Biological
2. Which of the following is a natural preservative?
A. Sodium benzoate
B. Citric acid
C. Salt
D. Metanil yellow
3. Which gas is used in airtight packets of potato wafers?
A. Oxygen
B. Nitrogen
C. Hydrogen
D. None of these
4. Which method uses ionizing radiation?
A. Dehydration
B. Irradiation
C. Freezing
D. Drying
5. Who developed the technique associated with pasteurisation?
A. Louis Pasteur
B. Isaac Newton
C. Alexander Fleming
D. C. V. Raman
6. When is World Food Day observed?
A. 5 June
B. 16 October
C. 14 November
D. 1 May
7. Which adulterant is mentioned in connection with red chilli powder?
A. Sugar
B. Brick dust
C. Salt
D. Oil
8. Under which Act was FSSAI established?
A. Food Safety and Standards Act, 2006
B. Right to Education Act, 2009
C. Environment Protection Act, 1986
D. None of these
Click here to view the MCQ answer key
- B. Quantitative
- C. Salt
- B. Nitrogen
- B. Irradiation
- A. Louis Pasteur
- B. 16 October
- B. Brick dust
- A. Food Safety and Standards Act, 2006
14. Quick Revision
| Topic | Key point to remember |
|---|---|
| Food spoilage | Undesirable changes in food. |
| Quantitative wastage | Loss in the quantity of food. |
| Qualitative wastage | Reduction in food quality. |
| Food protection | Prevention of spoilage by microorganisms and pests. |
| Food preservation | Preventing spoilage for a longer period. |
| Freezing | Low temperature slows biological and chemical reactions. |
| Inert gas packing | Nitrogen is used in airtight wafer packets. |
| Irradiation | Uses ionizing radiation. |
| Natural preservatives | Salt, sugar and oil. |
| Chemical preservatives | Vinegar, citric acid and sodium benzoate. |
| Pasteurisation | Heating followed by rapid cooling. |
| Dehydration | Removal of water by drying. |
| Food adulteration | Removal of important components or addition of inferior or harmful substances. |
| FSSAI | Established under the Food Safety and Standards Act, 2006. |
| World Food Day | 16 October. |
