Harmful or Contaminated food

Subject : 

Basic Science and Technology

Term :

Second  Term


Week 10

Class :

Basic 4 / Year 4 / Primary 4


Previous lesson : 

The pupils have previous knowledge of Balanced Diet  in their  previous lesson

Topic :

Harmful foods
Harmful foods e.g contaminated food
Bad feeding habits


Behavioural objectives :

At the end of the lesson, the pupils should be able to

  • Explain the meaning of bad eating habits
  • Explain the meaning of Harmful foods
  • List out examples of Harmful foods e.g contaminated food
  • List the examples of Bad feeding habits that must be discouraged .

Instructional Materials :

  • Wall charts
  • Pictures
  • Take Away Pack of Food .
  • Related Online Video on Classes of Food
  • Flash Cards

Methods of Teaching :

  • Class Discussion
  • Group Discussion
  • Asking Questions
  • Explanation
  • Role Modelling
  • Role Delegation


Reference Materials :

  • Scheme of Work
  • Online Information
  • Textbooks
  • Workbooks
  • 9 Year Basic Education Curriculum
  • Workbooks


Content :

What are bad eating habits ?

Bad eating habits are perpetual bad unwelcomed eating  behaviours that are not so welcoming that must be discouraged while eating at home , at the table or at social gatherings

Examples of poor eating habits are 

  • Eating irregularly in between meals
  • Eating too much sugary food
  • Eating too much fast food
  • Excessive consumption of processed food
  • Eating while walking on the roads
  • Taking large piece of food that may be difficult to chew or swallow
  • Talking while eating
  • Sleeping or lying down on your belly while eating
  • Very late supper
  • Eating in public places or buses


What are harmful or contaminated foods ?

Harmful or contaminated foods are foods that are no longer healthy , safe or hygiene for human consumption . These food items may not be good for eating because they are either expired, rotten , unripe, adulterated , contaminated , poorly stored or genetically modified .


Examples of  Food items that may easily be contaminated or become unsafe for eating  are 

  • Suya that is not well prepared with some moisture of water or blood
  • Genetically modified soft tissue chicken that are sold in most fast-food centers
  • Frozen or embalmed imported chicken
  • Raw meat publicly displayed for sales
  • Can or processed fish in tin
  • Beef in tin
  • Milk , cheese or ice cream
  • Eggs
  • Fruits
  • Uncovered food at the table


Effects of Eating Contaminated or Harmful Foods 


Foods become harmful when they contain disease-causing organisms, such as bacteria, fungi and viruses, or if they contain poisons

Harmful foods Harmful things present Harmful effects
Rotten vegetable, over ripe fruits, unripe fruits Bacteria Stomach ache, vomiting,
Foods contaminated by dirty water or faces Bacteria Cholera, diarrhea, typhoid fever
Foods exposed to flies Bacteria Dysentery, diarrhea
Expired canned foods or drinks Poisons produced by bacteria or fungi Food poisoning, colon cancer, Persistent abdominal discomfort,



The topic is presented step by step


Step 1:

The class teacher revises the previous topics


Step 2.

He introduces the new topic


Step 3:

The class teacher allows the pupils to give their own examples and he corrects them when the needs arise




The class teacher wraps up or conclude the lesson by giving out short note to summarize the topic that he or she has just taught.

The class teacher also goes round to make sure that the notes are well copied or well written by the pupils.

He or she does the necessary corrections when and where  the needs arise.



  1. Explain the meaning of bad eating habits
  2. Explain the meaning of Harmful foods
  3. List out examples of Harmful foods e.g contaminated food
  4. List the examples of Bad feeding habits that must be discouraged .
  5. What is balanced diet ?
  6. What is food poisoning ?




Prepare for the next lesson by reading for Revision



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