E.g. If you leave moist food in a cupboard and forget about them, they will go bad.
The tiny spores (tiny reproductive cells in bacteria and fungus) of bacteria and fungi land on the foods from the air. As they grow, the bacteria and fungi produce chemicals that allow them to dissolve the foods. These chemicals can make us ill. Then we are said to have food poisoning.
Several ways to stop or slow down the decay of foods
c) Chemical preservatives
Bacteria and fungi need warmth to grow. In low temperatures they stop growing.
5) Fresh foods
6) Cooked foods
Bacteria and fungi need moisture to grow. They cannot grow in dried foods which are stored in sealed containers.
8) *Chick peas
* Pulses (Edible seeds of various pod-bearing plants)
Safe chemicals can be added to food to stop the bacteria and fungi from feeding and growing.
E.g. – 1) A lot of sugar is added to fruit to make jam and marmalade.
2) Vinegar, used in pickles, is too acid for bacteria and fungi to be able to grow.
3) A lot of salt is added when bacon is produced.
Canning and bottling
1) Some foods like fruits and vegetables are heated strongly to destroy or kill any germs such as bacteria and fungi.
2) Then the foods are sealed in airtight containers.
3) So that no more bacteria and fungi can get into the food until the can is opened.
It is important to be careful when we handle stored or preserved food. The surface where we prepare food need to be very clean, or bacteria will spread to the foods we eat and may make us ill.
A bacterium can divide into two new bacteria in minutes.
1) In our nose
2) In our throats
3) In our cuts and sores
4) On our skin
5) On our hands
February 5, 2013