John tyndall and ferdinand cohn discovered the existence of bacterial and established the term sterile.

John tyndall and Ferdinand Cohn discovered that there were two types of bacteria exisitng in nature: those who are affected by heat leading eventually to their demise and those that are resistant or immune to a certain degree of heat. This finding is important in the devising of the sterilization process which it was recognized as a method of killing bacteria by applying heat to the medium. Later on, Cohn discovered the existence of endospores. Today, there are various types of bacteria, the thermobacteria, the cryobacteria- bacteria that are prone to cold temperatures and the bacteria that thrive on temperatures from 30-35 degrees normally.