Microbes are a real danger to the Station's material because they will eat almost anything. All materials used in the Station are tested to see if they can resist fungus, and a paint with germ-killer in it is also used. Finally, the Station crew cleans surfaces by hand to keep them free from germs. All these steps to cut down microbes in the Space Station should help keep the Station crew in good health while they spend months living in space. There are lots of different kinds of bacteria.
Bacteria are very tough and can live just about anywhere.
Some bacteria can make you sick, but many others are good. Bacteria were among the very first life forms on Earth. A fungus often looks like a very tiny plant, but these things called fungi are more closely related to animals. Many fungi get their food from soil, and others eat dead plants and animals. A mushroom from the food market is a fungus you can eat.