Sterility indicates the elimination (death) of all viable life forms and their germinative elements such as eggs, spores and endospores. Sterility and asepsis refer to different conditions. Three terms are often used when talking about this subject and they are: sterilization, disinfection, and asepsis. Medical sterilization is a much broader field than food irradiation. Whichever scientifically based, predictive testing procedure is used, it is very difficult to devise a test system that accurately replicates the conditions with the human body, so predictiveness is never going to be guaranteed. It is important to note that no test, however foolproof its design, can ever be considered a definitive predictor of clinical performance. By using a combination of chemical and mechanical analysis techniques, both manufacturing and decontamination processes can be optimized to ensure a safe and effective product. However, in some instances, one portion of the device is intended to come into contact with skin, blood, or body fluids, while other parts may remain exterior to the human body and may be less sturdy.Ĭhemical characterization of residues that may be adsorbed onto surfaces and mechanical testing to ensure functionality should provide sufficient information to evaluate the potential success of cleaned and disinfected/sterilized medical devices. Usually medical devices are made of fairly robust materials that can withstand corrosive blood and body fluids. Successful cleaning, decontamination and sterilization/disinfection of medical devices and instruments require both the careful selection of materials and consistent monitoring of the procedures used to process them. Albert, in Developments in Surface Contamination and Cleaning, 2015 12 ConclusionĬleaning, during the manufacturing process, prepares medical devices for sterilization and sterile packaging. Conventional treatment and chlorination may not be enough to ensure safety.įor comparison, sterilization processes are normally specified as providing at least a 12-log reduction in all types of organisms.ĭavid E. This last is a problem because at least a 3-log reduction in Cryptosporidium is required in many regulatory regimes. We do not know which microorganisms these proxies represent, but we assume that if these easy to culture organisms made it through our process, many pathogens did too.Ĭonventional drinking water treatment processes prior to the disinfection stage give a 4-log reduction in CFUs, a 2-log reduction in coliforms, a 2-log reduction in (far smaller) Cryptosporidium and Giardia cysts and a 2-log reduction in (smaller still) viruses.Ĭonventional disinfection such as chlorination after such treatment give a 2-log reduction in CFU and coliforms, in viruses, but no reduction in (far smaller) Cryptosporidium cysts. We frequently use “indicator organisms” such as “colony forming units” or “coliforms” to stand in for the harder-to-test-for organisms which also tend to be markers of fecal contamination.Ĭonsequently, regulators tend to specify a certain number of colony forming units (CFUs) and coliforms per unit volume of water. Therefore, we tend to analyze all three types of process with respect to log reductions, whether that be in organisms in general or pathogens in particular.
This holds true whether we are using electromagnetic radiation, heat, or chemicals.
#Compare and contrast medical and surgical asepsis. plus
This illustration tells us that three things matter in the removal of all life from a system: how much life you started with, plus both the intensity and duration of your killing agent.
Excerpted from Canning Principles, available online at (accessed 2 November 2017). Courtesy: Food & Agriculture Organization of the United Nations.
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