School of Infection & Immunity

Destruction and disposal of Cultures

Each lab group must have a written policy appropriate for the destruction of any viable micro-organisms used.

Microbiologically contaminated material should only be washed up or disposed of after effective treatment with disinfectant or after additional sterilisation by autoclaving or incineration.
For pelleted material, cell supernatants or spilled live organisms (included contaminated glassware, swabs, etc) use fresh 1% chloros (1 in 100 dilution; 10,000 ppm) for at least 1 hour.
For pipettes and mildly contaminated glassware use 0.25% chloros (1 in 400 diluton; 2,500 ppm), prepared fresh daily, for at least 1 hour.

Used solutions should be disposed of down the sink with copious (at least 20-fold) volumes of water. If there is to be no additional sterilisation by autoclaving, disinfection should be extended for at least 24 hours.

Autoclaving of contaminated material should be carried out using a 'kill' run (ie, 134degC for 18 minutes). Polypropylene tubes (but not polycarbonate ones) can be autoclaved. Polycarbonate tubes may be disinfected by soaking them in Hibitane 1/2000 or hypochlorous acid solutions (eg Presept) but not in phenolic disinfectants.

All microbiologically contaminated materials must be sterilised before disposal. Liquid cultures can be killed either by chemicals or by autoclaving. Culture plates should be autoclaved. Culture flasks, centrifuge tubes, bottles and caps must be properly sterilised after use with live cultures. Glassware should be autoclaved. Polypropylene tubes (but not polycarbonate ones) can be autoclaved. Polycarbonate tubes may be disinfected by soaking them in 0.25% chloros.
Bags containing items awaiting autoclaving should be further contained with a robust container such as a plastic bin.