3. Levels of decontamination
This page explains various processes you can use depending on the level of decontamination required.
Physical cleaning
Successful disinfection and sterilisation are dependent on the number of microorganisms initially present. Therefore, it can be important to physically clean before effective disinfection and sterilisation. Various powder or liquid detergents are available which may need to be diluted in hot water.
Ultrasonication
This liquid-based cleaning method uses cavitation (rapid formation and collapse of minute bubbles in liquid). Treated items must be submersible.
Sterilisation
In contrast to disinfection, this is an absolute term denoting destruction of all microorganisms, including bacterial spores.
Disinfection and sterilisation using heat
Heat treatment is the most effective routine means of destroying the infectivity of all microorganisms, including BBVs, and mainly involves the use of autoclaves (pressure steam sterilisers).
Boiling and dry heat ovens do achieve raised temperatures that can kill microorganisms. However, they may lack the required level of heat delivery and treatment control offered by steam sterilisers, so are less reliable.
Whatever system is used must be maintained and periodically tested to ensure that it is achieving sterilising conditions consistently.
Autoclaving
Saturated steam under pressure provides reliable sterilisation of waste and autoclavable, reusable equipment.
Thermal washer disinfection
Use a combination of physical cleaning and thermal biocidal action to achieve disinfection of contaminated, reusable items.
Dry heat
Dry heat sterilisers offer another method of sterilisation. It is effective provided that the steriliser has an automatic controller that will ensure appropriate temperatures are achieved throughout the load.
Boiling
Boiling does not necessarily remove all biological agents, but it may be used for disinfection.
Incineration
Incineration is an alternative to autoclaving for waste decontamination. It requires an effective means of temperature control and assurances that the system is suitable for dealing with infectious and other waste, such as plastics.
Disinfection
This is a process of reducing the numbers of microorganisms to an acceptable level.
Chemical disinfection
The protein in blood and other body fluids may confer a protective effect for viruses, and in some cases may reduce the effectiveness of chemical disinfectants.
It is reasonable to assume that, because of the viral robustness, any preparation effective against hepatitis B virus will also be effective against other BBVs.
Disinfection of contaminated surfaces with bleach solution (minimum 1000 parts per million (ppm) active chlorine) is known to be effective for the inactivation of BBVs, but bleach is also susceptible to inactivation by organic soiling. This underlines the need for prior cleaning when disinfecting any soiled items, to reduce the organic load.
Some chemical disinfectants have been tested for their activity against BBVs in the presence of whole blood or plasma (the fluid component of blood) to simulate in-use conditions.
Removal of organic material should not be done manually if operator safety is compromised. However, in these situations it may be achievable by alternative means, for example using an ultrasonication tank or washer disinfector.