LABORATORY WASTE
The procedure for the laboratory waste decontamination
Autoclave Quality Assurance Program for bio-hazard decontamination
Autoclaving is an accepted procedure for decontamination of certain bio-hazardous waste. Biological cultures and stocks, contaminated solid waste, liquid waste, and small animals carcass waste can be sterilised through autoclaving. After sterilisation in a steam autoclave,
these materials are considered non-infectious. Except for animal carcasses, this bagged waste can be disposed of as ordinary trash; however, it is recommended that autoclave bags containing sterilised waste be placed in an opaque trash bag prior to disposal. Materials that contain hazardous chemicals or radioisotopes are not to be autoclaved.
To ensure that the bio-hazardous waste is properly decontaminated during autoclaving, the following procedures should be followed.
1. Infectious waste must be treated in an autoclave for a minimum of 30 minutes at 121°C (250°F); however, the total processing time required to decontaminate infectious waste depends on the specific loading factors (container type, water content, quantity, etc.). A total processing time of 60 minutes is recommended for gravity displacement autoclaves and 10 minutes for vacuum-type autoclaves (132°C).
Sterilisation by autoclaving is accomplished through exposure and penetration of the contaminated material by superheated steam for an adequate amount of time. Since steam will not penetrate a sealed plastic autoclave bag, bags containing dry loads must not be tightly sealed (rubber band closures will allow bags to “breath”) or adequate amounts of water must be added to the load. Consult the manufacturer’s instruction manual for sterilizing materials inside plastic autoclave bags.
2. All autoclaved waste must include a steam sterilization indicator (the use of biohazard bags with a “built-in” indicator is recommended).
3. Steam autoclaves used to treat infectious waste must operate at a minimum temperature of 121°C. The operating temperature of the autoclave must be verified for each run by maintaining a record of temperature either as a chart or paper tape recording or a manual recording in a logbook.
4. For autoclaves used for bio-hazardous waste, a monthly basis test should be performed by using ampoules containing heat resistant spores (Bacillus stearothermophilus) placed in the centre of an autoclave load. In conjunction with the Bacillus stearothermophilus testing, measure and record the maximum temperature achieved during the autoclave cycle through the use of a maximum registering (or “holding”) thermometer.
5. Record of Bacillus stearothermophilus and maximum autoclave temperature recording must be maintained for a minimum of one year.
