sterilization - the destruction of all microbial life, including bacterial endospores.
disinfection - the elimination of virtually all pathogenic microorganisms on inanimate objects with the exception of large numbers of bacterial endospores, reducing the level of microbial contamination to an acceptably safe level.
antisepsis - the application of a chemical to living tissue to prevent infection.
decontamination - all of the above. Decontamination is any activity that reduces the microbial lode to prevent inadvertent contamination or infection. The appropriateness of a decontamination procedure is situationdependent. For example, surgical instruments must be sterile but this level of microbial killing is unnecessary for Environmental surfaces such as floors and walls.
Disinfection encompasses a continuum of outcomes in terms of the types of organisms destroyed. Microorganisms can be grouped as following in terms of decreasing resistance to disinfectants: bacterial endospores (B. subtilis, clostridium spp); Mycobacteria; nonlipid or small viruses (poliovirus, rhinovirus); fungi ; vegetative bacteria; and, lipid or medium sized virus (herpes simplex, HIV, HBV).
The table at the end of this section provides a framework for the selection of the appropriate disinfectant. The label on a commercial product will note its type of ‘cidal’ action (‘tuberculocidal’, ‘sterilant’). These claims may not appear unless the manufacturer has submitted data to the EPA supporting such claims. The lists of EPA registered disinfectants can be obtained from your campus EH&S office or found at http://www.epa.gov/oppad001/chemregindex.htm
The EPA does not independently audit such results and research indicates that in real life situations some products do not perform as claimed. This result from manufacturers testing their products in best-case situations, e.g., on a smooth surface, at an optimal pH, in a buffer solution instead of a solution containing organic material which partially inactivates some disinfectants. For high risk pathogens, investigators may devise their own test to confirm a product’s claim or consult EH&S.
When using any disinfectant:
The Bloodborne Pathogens Standard requires that products labeled "tuberculocidal hospital disinfectant" be used on surfaces and equipment when the Standard is in force. Household bleach, usually at a 1/10 dilution, also satisfies this requirement and may be used in these cases. Bleach solutions lose potency over time and should be prepared fresh daily.
Summary of Disinfectant Activities