It can be seen in everyday life. It has been around for many years. It can be any color we can imagine. Look around, you can probably see some of it right now. What is it?

They are strong when white.
They can be easily shaken and weakened,
Easily stained and infected;
None was found at first, then one appear,
Afterwards, more are seen and thirty two appear at last;
They all stand waiting for their prey.
The foods you eat are their prey.
They all are in you. Who are they?