Sanitization vs. Disinfection

The terms disinfection and sanitizing or sanitization are often misused or misunderstood. The following generally accepted definitions are provided:

Sanitize: To reduce the number of microbial contaminants to a safe or relatively safe level as may be judged by public health requirements or to a significant degree where public health standards have not been established.

Disinfection: The destruction of pathogenic or other harmful microorganisms or the inactivation of viruses.  Usually refers to the vegetative forms of pathogenic bacteria, but not necessarily bacterial spores.

Both of these processes refer to chemical or physical means applied directly to inanimate surfaces.  Disinfection is generally intended for patient-care items in health care facilities or home care while sanitization generally applies to environmental surfaces not directly involved in patient care.  Sanitization is also the level of antimicrobial activity usually associated with food service and food processing facilities.

We frequently hear references to the disinfection of floors, walls, bathroom fixtures, carpets, etc.  In reality, these surfaces are sanitized, not disinfected.  We routinely sanitize eating utensils, dishes, cookware, and food contact surfaces, yet there is a sense that we are providing less than adequate microbiological control when we refer to sanitizing a floor or other surfaces that do not normally contact mucous membrane or skin that is not intact.  Aside from the lack of necessity to disinfect such environmental surfaces, it is impractical to do so.

Disinfection requires contact between the disinfectant and the surface to be disinfected for at least ten minutes under moist conditions.  We can disinfect patient-care items by immersing them in a disinfectant solution for ten minutes, but we cannot do this with environmental surfaces.  While we may use a disinfectant product, such as SaniMaster 5, on floors, furniture, bathroom fixtures, etc., we do not  attain  a  ten-minute  exposure  or contact time under moist conditions, and we are really sanitizing these surfaces rather than disinfecting them. Good cleaning and physical removal of microorganisms is the primary goal when we treat environmental surfaces.  The use of a disinfectant product in the sanitizing is not the most important factor and may not even be necessary.  The Centers for Disease Control and Prevention (CDC) acknowledge that environmental surfaces are rarely associated with transmission of infections to hospital patients or personnel and that physical removal by scrubbing is as important, if not more so, than any antimicrobial effect of the cleaning agent used.

This discussion is intended to clarify the differences between disinfection and sanitization, and where these two levels of antimicrobial activity apply under actual in-use conditions in the environment.

Edward A. Schmidt, MPH, CIC
Environmental Microbiologist/Environmental Sanitarian
Infection Control Practitioner