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Decontamination

Decontamination is defined as the reduction of microorganisms to an acceptable level. Methods applied to reach this goal can vary and most often include disinfection or sterilization. Generally speaking, disinfection is used when the acceptable level of microorganisms is defined as being below the level necessary to cause disease. This means that viable microorganisms are still present. In contrast, sterilization is defined as the complete killing of all organisms present. Depending on the circumstances and tasks, decontamination of a surface (e.g., lab bench) is accomplished with a disinfectant, while decontamination of biomedical waste is done by sterilization in an autoclave.

Many different terms are used for disinfection and sterilization. The following are among the more common in biosafety:

• Antimicrobial - An agent that kills microorganisms or suppresses their growth and multiplication.
• Antiseptic - A substance that inhibits the growth and development of microorganisms without necessarily killing them. Antiseptics are usually applied to body surfaces.
• Biocide - A general term for any agent that kills organisms.
• Chemical germicide - A chemical or a mixture of chemicals used to kill microorganisms.
• Disinfectant - A chemical or mixture of chemicals used to kill microorganisms, but not necessarily spores. Disinfectants are usually applied to inanimate surfaces or objects.
• Microbicide - A chemical or mixture of chemicals that kills microorganisms. The term is often used in place of "biocide", "chemical germicide" or "antimicrobial."
• Sporocide - A chemical or mixture of chemicals used to kill microorganisms and spores.

When choosing a method of decontamination, it is important to consider the following aspects:

• Type of biohazardous agents, concentration and potential for exposure;
• Physical and chemical hazards to products, materials, environment and personnel.

Decontamination: Cleaning Laboratory Materials

Biosafety Manual Table of Contents