Contamination by unwanted microorganisms will affect your results and can potentially result in growth of pathogens
Avoiding pathogens - the petri dishes and culture medium must be sterilised before use (e.g. by heating to a high temperature), to kill any unwanted microorganisms that may be on them
Avoiding pathogens - If an inoculating loop is used to transfer the bacteria to the culture medium, it should be sterilised first by passing through a hot flame
Avoiding pathogens - After transferring the bacteria, the lid of the petri dish should be lightly taped on - to stop microorganisms from the air getting in
Avoiding pathogens - The petri dish should be stored upside down - to stop drops of condensation falling onto the agar surface
