How are microorganisms used in food?

bacteria, e.g. yogurt

Microorganisms are used in brewing,winemaking,baking,pickling and other food making processes.

It is usually used at the beginning except for mushrooms. Mushrooms are decomposers, which feed on dead bodies of animals.

Odds are, you'll find some there already. Usually a few won't hurt you, but many can get you sick.

Yes. They are pretty much everywhere on earth and there is some evidence that they may also be in objects in space.