Chapter 7: Food Spoilage and Preservation

Food Spoilage and Preservation Introduction

Have you ever bought meat and it decays in a day? What about someone pouring away left-over food from the previous night’s supper because it has gone bad and has a bad taste and smell. This is called food spoilage. How can it be prevented?
In this chapter, you should be able to recognise how the food goes bad and the possible methods of preserving different types of foods.
7.1: Causes of Food Spoilage and its Effects
Food can easily go bad. For example, if you leave food on a plate for a night. Itcan easily go bad. Have you ever seen bread looking like one in figure 7.1 or an apple like one in figure 7.2? Some of the spoilt foods have different colours and hair-like structures growing on them. These hair like structures are moulds.

In activity 7.1 , you are going to discover, the various causes of food spoilage in our homes
Activity 7.1: Recognising the causes of food spoilage
What you need: notebooks, braille paper, stylus, slate, Perkins brailler.
What to do:
In groups:
1.Discuss the meaning of the phrase ‘food’ and “spoilage”.
2.Discuss the possible causes of food spoilage in your homes.
3.Write down how food spoilage can be prevented.
4.Design a power point presentation with clear illustrations (use charts if power point presentation is not supported).
5.Present your work to the rest of the class.
6.Individually write or braille the meaning, causes and preventive measures of food spoilage.

7.2: Factors Promoting Growth of Micro-organisms on Food
The microorganisms that cause food spoilage are commonly bacteria and fungi. For example, in Figure 7.3, the black spots on bean pods are fungi spoiling the pods.

Some people are able to keep food safe for longer periods of time than others because they control factors that affect growth of micro-organism on food. What would be those factors? In Activity 7.2, you will identify the factors promoting growth of micro-organisms on food.
Activity 7.2: loentlfytng factors promoting growth of Micro-organisms on food and ways of preventing food spoilage
What you need: notebooks, braille paper, stylus, slate, Perkins brailler

What to do
In groups, study the story below and answer the questions that follow:

During preparations for Keizi’s introduction party, her parents bought meat, lemons; water melons 2 days before the party. The meat was too much and so they opted to put some in the refrigerator, roast some and a little of it was just put in a sauce pan since they had a plan of eating it the next day. That day they
ate half of the water melon leaving the other half. They took dawa tea in the evening with some potions of lemon leaves and sliced halves to be used later.
Unfortunately, the meat in the saucepan and the remaining half of the water melon were spoilt unlike the other foods.

1. Identify the factors that could have led to the spoilage of the various foods.
2. Explain why the foods went bad
   a) Meat in the saucepan
   b) Half of the water melon
3. Explain why the following foods did not go bad
   a) Roasted meat
   b) Meat in the refrigerator
   c) Remaining halves of the lemons

4. Assuming they had also bought fish, milk and cassava tubers. How best would they have preserved them?
5. Present your work to the rest of the class.
6. Individually write or braille your notes.
   From Activity 7.2, you have realised that food poisoning is costly especially health wise.
   7.3: Principles and Methods of Food Preservation
   Much as you can preserve meat by putting it in a refrigerator, it is not advisable to put it in a deep freezer. In Activity 7.3, you will identify the principles guiding different methods of food preservation.

Activity 7.3: Identifying the principles and methods of food preservation
What you need: notebooks, braille paper, stylus, slate, Perkins brailler
What to do:
As a class:
1.Listen to a visitor who has come to your class to tell you about the principles of different methods of food preservation.
2.Note down or braille the method talked about, the food it preserves and the dos and don’t of each method.
3.Summarize your information in a table.
4.In groups, compare the contents of your tables.
5.Present your work to the rest of the class.
6.Individually write or braille your notes.

What you need: notebooks, braille paper, stylus, slate, Perkins brailler.
What to do:
Study the conversation between Ebo and Edithen answer the questions.
Ebo: Hy Edi, i need your help.
Edi: What is it my friend?
Ebo: / have been buying food stuffs and they go bad after a few days!
Edi: Oh!Sorry……….Wheredo you keep them?
Ebo: I put them on a flow in the kitchen.
Edi: My friend, you need to keep them in a proper place like a cup board, freezer and
the dry ones in a cool dry place.
Ebo: Howcan iprotectthem from flies? Because ialways find a lot of them on tomatoes.
Edi: Proper washing ofutensi/s, covering them and also removing the rotten ones.
Also try to dry some foods properly like cassava, millet, and others.
Ebo: Haaaa…… Cant buy canned food or packed food?
Edi: Yesyoucan. But you need to buy mostly those from our country.
They are good.
Ebo: Thankyou for all this.
lam going to improve.

Task:
From the conversation below, identify the following.

1. Ebo’s practices that were leading to food spoilage.
2. Advice his friend Edi gave him.
3. Other ways Ebo can use to preserve his food.
   7.4: Food Poisoning and Treatment
   When microorganisms grow on food, they digest it and produce wastes. These wastes are toxins and poisons. These can bring abnormal functioning of our body systems when one eats food with growing microorganisms like fungi and bacteria.
   Symptoms of Food Poisoning
   Many people in our communities show symptoms resulting from food poisoning absolutely without their knowledge. Your symptoms depend on what caused you to get sick. In Activity 7.5, you will identify the symptoms of food poisoning and first aid for poisoning.

Activity 7.5: Identifying symptoms of food poisoning and first aid for food poisoning
What you need: notebooks, braille paper, stylus, slate, Perkins brailler.
What to do:
In groups:
Read a dialogue between Maria and Moses and answer the questions that follow.
Maria: Hello Moses, you have been lost!
Moses: Hello Maria, I have been sick with stomach-ache, vomiting, diarrhoea, abdominal pain and fever, see Figure 7.5.
Maria: Oh sorry Moses, what could have caused that?
Moses: You see Maria, it all started after eating lunch on Thursday.
Maria: What did you eat for lunch?
Moses: ummmm……remains of our previous nights’ supper

Task:

1. List the major causes of food poisoning.
2. State the common symptoms associated with food poisoning.
3. How can you help someone with symptoms of food poisoning.
4. Write or braille a report and present to the rest of the class.
   Ways of Helping a Food Poisoning Victim
   You usually get it from eating food or drinking water that is contaminated with bacteria, viruses, parasites, or toxins created from these When you have food poisoning, the first thing you want is relief.. While some cases last longer, it’s usually gone within a few days. How can you help somebody who has food poisoning?
   Attililtv 7.6: Exploring ways of helping someone who has had food poisoning
   What you need: notebooks, braille paper, stylus, slate, Perkins brailler.
   What to do:
   In small groups, discuss about food poisoning. Use the following guiding questions:
5. 1. Food poisoning is usually more dangerous to some people than other. List them.
6. 2. What can you do at home to help someone who has food poisoning?
7. When you are taking care of a person having food poisoning.
8. Which symptoms can make you to call the doctor?
9. Describe how food poisoning treated.
10. Write or braille your findings and present to the rest of the class.