How could you tell if one of the colonies on your pure plate was a contaminant from the environment and did not come from your original culture? b boldi italicsu underline bulleted list numbered list superscript subscript?
To tell if a colony on a pure plate is a contaminant or not, you can have a second plate that is closed off to the surroundings to see if that colony arises on its own or if it only arises when exposed to the environment.
