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Of all the methods available for sterilization, moist heat in
the form of saturated steam under pressure is the most widely
used and the most dependable. Steam sterilization is
nontoxic, inexpensive, rapidly microbicidal, sporicidal, and
rapidly heats and penetrates fabrics. Like all sterilization
processes, steam sterilization has some deleterious effects on
some materials, including corrosion and combustion of
lubricants associated with dental headpieces; reduction in
ability to transmit light associated with laryngoscopes; and
increased hardening time with plaster-cast.
The basic principle of steam sterilization, as accomplished in
an autoclave, is to expose each item to direct steam contact
at the required temperature and pressure for the specified
time. Thus, there are four parameters of steam sterilization:
steam, pressure, temperature, and time. The ideal steam for
sterilization is dry saturated steam and entrained water
(dryness fraction >97%). Pressure serves as a means to
obtain the high temperatures necessary to quickly kill
microorganisms. Specific temperatures must be obtained to
ensure the microbicidal activity. The two common
steam-sterilizing temperatures are 121°C (250°F) and 132°C
(270°F). These temperatures (and other high temperatures)
must be maintained for a minimal time to kill microorganisms.
Recognized minimum exposure periods for sterilization of
wrapped healthcare supplies are 30 minutes at 121°C (250°F) in
a gravity displacement
sterilizer or
4 minutes at 132°C (270°C) in a prevacuum sterilizer. At
constant temperatures, sterilization times vary depending on
the type of item (e.g., metal versus rubber, plastic, items
with lumens), whether the item is wrapped or unwrapped, and
the sterilizer type. The two
basic types of steam sterilizers (autoclaves) are the gravity
displacement and the dynamic-air-removal sterilizers.
Weekly testing is minimum:
Steam and low temperature sterilizers (e.g., hydrogen peroxide
gas plasma, peracetic acid) should be monitored at least
weekly with the appropriate commercial preparation of
Geobacillus stearothermophilus spores. If a sterilizer is
used frequently (e.g., several loads per day), daily use of
biological indicators allows earlier discovery of
equipment
malfunctions or procedural errors and thus minimizes the
extent of patient surveillance and product recall needed in
the event of a positive biological indicator. Each load
should be monitored if it contains implantable objects. If
feasible, implantable items should not be used until the
results of spore tests are known to be negative.
See also
www.cdc.gov/oralhealth/infectioncontrol/faq/sterilization_monitoring.htm
See ATS, Inc. complete line of steam sterilization monitoring
(In-Office or
Mail-In) and related
Supplies.
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DID YOU KNOW?
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Autoclave Testing Service, Inc. is one of the first companies
nationwide to offer a
Mail-In sterilizer
monitoring service using biological indicators. Serving the
healthcare industry throughout the United States and Canada since
1986, we have thousands of satisfied customers.
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We have on-line test results
allowing you to access your results at your convenience! Your
Sterilizer Test Report (STR) is posted
on-line upon completion of
culturing, offering minimum turn-around time.
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We have 24-hour test results for Steam sterilizers!
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We have a comprehensive Glossary of Terms related to the sterile
processing area (scroll below to view the Glossary). This is
invaluable information, assisting you with this important area of
your facility.
ATS, Inc. now
stocks sterilization pouches, sterilizer cleaners, chemical
indicator products, sterilizers (new and used), ultrasonic cleaners,
water distillers, and more! (see
Supplies).
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