6.1—Culturing microorganisms and aseptic technique

Microbial culture requires sterile media, equipment and technique so that the organism being studied is not outcompeted or confused with contaminants. Aseptic handling protects the sample, the investigator and the environment.

Sterilise media and apparatus, disinfect the work area, minimise exposure of plates or broths, and label controls. Compare growth with a negative control to detect contamination.

If a plate exposed briefly during inoculation grows colonies outside the intended streak, those colonies may be contaminants rather than evidence about the tested organism.

A clear plate does not prove sterility, and opening a culture outside controlled conditions can create a safety hazard. Use the required containment and disposal procedure.