Sterile equipment and reagents

Aseptic technique requires that all surfaces, equipment, and reagents that may come into contact with the sample are sterilized or disinfected to avoid contamination. Different sterilization and disinfection techniques exist depending on the application. The most common techniques when culturing a sample in the lab are listed below.

Table showing different objects, the disinfection or sterilization method used, and the mechanism of sterilization. First object: work surface. Method: alcohol. Mechanism: 70% or greater concentration of alcohol such as ethanol disrupts membranes. Next object: media and pipette tips. Method: autoclave. Mechanism: Wet heat coagulates proteins and kills cells, containers should be opened only in sterile work area and neck of bottles should be sterilized in bunsen burner flame. Next object: small equipment including culturing loops and spreaders. Method: bunsen burner or pre-sterilized. Mechanism: The extreme heat of the blue flame on a bunsen burner kills cells. Pre-sterilized, typically autoclaved, equipment must be used in the biosafety cabinet. Last object: hands. Method: disinfect or gloves. Mechanism: When using the bunsen burner, hands should be thoroughly washed or disinfected before and after culturing. When using the biosafety cabinet, gloves should be changed.