Unit 1-2

Friends or Foes?

Tapai is a popular food in Malaysia. It is made from glutinous rice or tapioca. Yeast is added to make tapai.

Yeast is also used to  help dough to ride in baking  bread. 

                              

Tempeh is another kind of food that uses yeast. It is made from soya bean. Look at the picture closely. Can you see the white structures?

Bacteria and fungi cause dead organisms to decay to form natural fertilizers.

Some bacteria can be used to make cheese and yogurt.

   Fungi are used to produce antibiotics

Here are some harmful effects of microorganisms.

Some microorganisms that enter the body can cause illness. 









Eating food contaminated with microorganisms can cause food poisoning.





Bacteria act on the food remains between the teeth. This produces acid which causes tooth decay. 

Food turns bad because of bacteria and fungi.






Harmful microorganisms can cause many types of diseases.

Some diseases can easily spread from one person to another. They are called contagious diseases. Examples are influenza, measles, mumps, conjunctivitis and chicken pox.