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Decontamination: Ways to Decontaminate

Heat

In order to kill microbial agents, heat can be applied in dry or wet form. The advantage of wet heat is a better heat transfer to and into the cell resulting in shorter exposure time and lower temperature. Steam sterilization uses pressurized steam at 121-132°C (250-270°F) for 30 or 40 minutes. This type of heat kills all microbial cells including spores, which are normally heat resistant. In order to accomplish the same effect with dry heat in an oven, the temperature needs to be increased to 160-170°C (320-338°F) for periods of 2 to 4 hours.

Decontamination of Biohazardous Waste by Autoclaving
Autoclaving is accepted as a safe and effective procedure for sterilization. There are currently over one hundred fifty operating autoclaves on the MSU campus. To ensure that any biohazardous waste created by the MSU community is properly decontaminated, the ORCBS tests each autoclave on an annual basis. Biological and chemical tests are used to monitor the autoclave cycle inside the chamber. Ampoules with heat resistant spores ( Bacillus stearothermophilus ) and steam sterilization integrator strips are used to indicate that adequate sterilization conditions are reached.

• All autoclaves used for decontamination of biohazardous waste need to be registered with ORCBS and tested on at least an annual basis.
• Strong oxidizing material (chemicals) must not be autoclaved with organic material: Oxidizer + Organic Material + Heat = Possible Explosion
• All biohazardous waste must be placed in orange biohazard bags with a heat sensitive "Autoclaved" indicator.
• Prior to autoclaving, a biohazard bag containing waste must be kept closed to prevent airborne contamination and nuisance odors. However, when autoclaving, the bag must be open to allow the steam to penetrate. Upon removal of the bag from the autoclave, it should be closed and disposed of in an opaque (black) waste bag.
• It is recommended to add water to each bag before autoclaving.
• Autoclave biohazardous materials using the recommended parameters posted on the autoclave.

Decontamination: Liquid Chemicals Used as Disinfectants

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