Louis Pasteur’s breakthrough discoveries unlocked the world of microscopic organisms that live inside our bodies.

Now, normally, you can get rid of that bacteria-ridden ball either when you sneeze or blow your nose. But if you decide to eat it instead, it stands to reason that you're putting yourself at risk ...

Microorganisms are tiny. They are so small they can only be seen with a microscope. Yeast is a helpful microorganism which makes bread rise. Bacteria is a microorganism which breaks down plants ...