Food spoils when it gets old. This is because food contains bacteria which is invisible to the naked eye. Over time, the bacteria grows and breaks down proteins and other substances found in food. When that happens, we can say that the food is spoilt.
How can we tell food is spoilt?
Spoilt food can have an unpleasant smell or can taste different. It can also become softer than normal and change in colour or texture.
Why does spoilt food make us feel ill if we eat it?
When we eat spoilt food, we are consuming the by-products created bacteria when it breaks down food. These include acids and other waste products. This can give us a stomach ache, cause loose motions or make us very ill.
What is bacteria?
Bacteria are unicellular micro-organisms that are found almost everywhere. Although most bacteria are harmless to people, the build-up of certain varieties can lead to food poisoning. Beneficial effects of bacterial action include breaking down organic waste, producing antibiotics and making various food.
Is all bacteria harmful?
Bacteria can be useful too. Beneficial effects of bacterial action include breaking down organic waste, producing antibiotics and making various food.
For example, bacteria breaks down the ingredients of milk to make yoghurt and cheese.
Take a piece of bread and leave it in a closed jar or outside for a few days and see what happens. Write down 10 places where you would find bacteria in your home and cross check with friends or family. How does a refrigerator help in storage of food?