Food Preservation

Our food provides us with energy. However, when this food is left for a few days, it undergoes changes.It turns bad.


Mighty Microbes
Food undergoes changes that makes it spoil. These changes can be detected by their smell, taste, touch or sight. Spoilt food is unsafe to eat.

Fish is no longer fresh when the flesh has changed texture. It is no longer firm when pressed with a finger. It also has an unpleasant smell.

Stickiness under the chicken wings and darkening of their tips indicate spoilage.

We are blessed with many varieties of food. However, our food may be infected with microorganisms. Microorganisms such as fungi and bacteria can cause food to spoil.

                                                       

The fruit and vegetables above have been affected by moulds. They become mould. They become mouldy and change colour.


Food turns sour because the bacteria in it produced acids. A common examples is when milk turns. A common example is when milk turns sour, giving it an unpleasant taste.

Microorganisms need air and nutrient to grow. They grow on the surface of food when air is present. The food provide nutrient for them.

Since microorganisms are the main cause of food spoilage, how do we prevent it from happening?

WRAP IT UP!
1	Spoilt food is that is unsafe to eat.
2	Spoilt food has one or more of the following characteristics. Ø unpleasant smell Ø unpleasant taste Ø changed colour Ø changed texture Ø mouldy
3	Microorganisms present in our surroundings can cause food to spoil.
4	Microorganisms need certain conditions to grow. These conditions are air, water, nutrient, suitable temperature and suitable acidity.
5	Food preservation is a process of slowing down the food from becoming bad.
6	The ways to preserve food are bottling, canning, picking, drying, salting, vacuum packing, cooling, freezing, waxing, pasteurizing, boiling and smoking.
7	We need to preserve food so that they will last longer, easy to serve and transported as well as to reduce food wastage.

Check Your Understanding


     

1	Fill in the blanks with the correct words. (a) Food is heated before canning to       kill                      . (b)                        is the process of      drying food with smoke. (c) Freeze-dried food are easy to store         and                          .

2	Match each food with its correct preservation method.
	Pineapple	Fresh milk	Meat ball	Prawn
	Freezing	Drying	Pasteurization	Pickling

3	Which of the following is not a reason why we need to preserve food?
	A	For food to last longer.
	B	For food to be stored easily.
	C	To reduce wastage of food.
	D	To reduce the time taken for food to cook.

4	Arrange the steps to salt fish in the correct order.
	P	Clean the fish with water.
	Q	Rub salt into the fish.
	R	Remove the internal organs of the fish.
	A	P→Q→R
	B	Q→P→R
	C	P→R→Q
	D	R→P→Q
5	Daniel investigated the time taken for moulds to grow on a piece of bread. He took two pieces of bread and sprayed one of them with water. The results of his investigation are shown below.
	Bread		Time taken for mould to grow (day)
	Without water		4
	Sprayed with water		2
a	What is the purpose of this investigation?
b	In this investigation, indentify what did Daniel: i  keep the same? ii changes? iii observe?
c	Name other factors that allow moulds to grow.

                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                            

Vocobulary
English	Bahasa Melayu
bottling	pembotolan
canning	pengetinan
coarse salt	garam kasar
cooling	pendinginan
detected	dikesan
drying	pengeringan
freezing	penyejukbekuan
heating	pemanasan
pickling	penjerukan
preservation	pengawetan
salting	pengasinan
smoking	pengasapan
stickiness	melekit
unpleasant	tidak menyenangkan
vacuum packing	pembungkusan
waxing	pelilinan

Food preservation

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                   FOOD PYRAMID