What is Autoclaving?
Autoclaving is used to sterilize plastic and glass bottles, plastic caps, medical instruments, applicators, and numerous other items that can withstand high temperatures and pressures. Products or components used in the pharmaceutical or medical field require control of microbial levels during processing and handling. Autoclaving is one of the many options used to achieve microbial limit testing on these products.
When used in large industrial scale, the process is also called retorts. Autoclaving has been in use for more than a hundred years, particularly in laboratory settings.
How is it done?
Autoclaving uses high-pressure stream to achieve reliable sterilization. It is the preferred method of sterilization unless the material to be sterilized can be damaged by heat or moisture.
Sterilization in an autoclave is most effective when the organisms are either contacted by the steam directly or are contained in a small volume of aqueous (primarily water) liquid. Under these conditions, steam at a pressure of about 15 psi, attaining temperature of 121 C will kill all organisms and their endospores in about 15 minutes.
What plastic materials are safe for autoclaving?
Not all plastic materials are safe for autoclaving. Polypropylene (PP) and polypropylene copolymer (PPCO) containers can be autoclaved many times. Fluoropolymer products, such as Teflon PFA, FEP, or ETFE, can be autoclaved without problems. However, Polycarbonate (PC) containers can be autoclaved with caution, as they should not be exposed to alkaline detergents or steam additives, and they may withstand only up to 30 – 50 autoclaving cycles. Sterlizing PC reduces the mechanical strength of the material.
The following resins can not be autoclaved- HDPE, LDPE, PET, PETG. Each of these material can be successfully sterilized by gas (ethylene oxide formaeldehyde).
What living materials are safe for autoclaving?
The only recommended closure liners that can withstand autoclaving are rubber and Teflon.
How about Glass?
Glass is generally considered safe for autoclaving. When autoclaving glass bottles and caps together, make sure the cap is loosened prior to sending the components to autoclave to prevent the bottles from exploding. Many times an aluminum foil with autoclave tapes are placed to keep the inside of the bottle sterile. Autoclave tape will also turn black to help show the bottle has gone through the autoclaving process.
NOTE: Clean and rinse all items with distilled water before autoclaving.
Where can I get more information about Autoclaving?
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