Microorganisms can affect humans in many different ways. The microscopic creatures including bacteria,fungi and viruses can make you ill but most on your body help you digest food, protect against infection and even maintain your reproductive health. Microorganisms can live on the skin, in the nose, mouth and digestive gut but less than 1 % of the different types can make people sick. The major effects that they have one the earth is their ability to recycle the main elements that make up all living systems especially carbon, oxygen, and nitrogen. In food there are pathogenic microorganisms which can cause infections or intoxications and Saprophytic micro-organisms like probiotic bacteris are used in food processing.
