Understanding Cleanroom Apparel Sterilization

Understanding Cleanroom Apparel Sterilization
Sterilization is a process that is intended to destroyviableforms of microbial life including bacteria, molds, yeasts,viruses,protozoa, and algae (including bacterial spores) to anacceptablesterility assurance level (SAL). SALs were first used inthe foodcanning industry and refer to the degree to which an itemisexpected to be non-sterile after exposure to asterilizationprocess. While we use phrases like “terminalsterilization,” wemust remember that sterilization is a matter ofdegree orprobability. In a sterilization process, the natureofmicrobiological death is therefore described by anexponentialfunction, an expression of probability.

For instance, a SAL of 10-6 means that there is a one inamillion chance (probability) that a microorganism will remainafterthe sterilization process. However, while this probability canbereduced to a very low number, it can never be reduced tozero.ANSI/AAMI ST67:2003 contains a decision tree to be usedtodetermine the SAL for medical devices to be terminallysterilized.

Sterilization is necessary when microorganisms are acontaminant.Such cases would include surgery, the implantation ofmedicaldevices, or the injection of solutions into the body.Sometimes, thedevice, instrument, or solution can be sterilizedand packaged untilit is ready for use. Often, however,sterilization, regardless ofmethod, has a deleterious effect onthe product. In such cases, thealternative is asepsis, theprevention of contact withmicroorganisms. Aseptic processing ormanufacturing generallyrequires the use of a cleanroom andcleanroom apparel. A sterilecleanroom is often called a sterilesuite or aseptic cleanroom.These rooms are meticulously maintainedin a sterile condition byrigorous housekeeping and specialdecontamination proceduresgoverned by the FDA and detailed in theFederal Guidelines to GoodManufacturing Practice (GMP). Note: Ifyou see cGMP, the small case“c” stands for “current.”

Cleanroom garments used in aseptic cleanrooms must besterile.ANSI/AAMI ST67:2003 identifies the sterility assurancelevels forterminally sterilized products. Many companiesmanufacturingproducts in an aseptic clean-room require allcomponents used inaseptic processing, including cleanroom garments,to be terminallysterilized to 10-6SAL.

There are three typical methods of sterilizingclean-roomgarments: steam autoclaving, ethylene oxide (EtO), andionizingradiation (gamma or electron beam). While each hasadvantages anddisadvantages, gamma irradiation is the most popularmethod usedtoday.


Understanding Cleanroom ApparelSterilization  Understanding Cleanroom ApparelSterilization