3-3
Techniques of Sterilization Operator Manual 387366-389
3.2 Control
Measures for
Verifying
Sterilization
Process
There are three general control measures used to verify sterilization:
• Biological Measure, using live spores (see S
ECTION 3.2.1,
B
IOLOGICAL MONITORS)
• Chemical Measure, using an indicator to verify air removal (see
S
ECTION 3.2.2, CHEMICAL MEASURE (BOWIE-DICK TESTS)
• Testing for Prevacuum Efficiency (see S
ECTION 3.2.3, VACUUM
LEAK TEST)
These are discussed in the sub-sections below.
3.2.1 Biological Monitors A live spore test utilizing G. stearothermophilus is the most reliable
form of biological monitoring. This type of product utilizes controlled
populations of a controlled resistance, so that survival time and kill
time can be demonstrated.
To verify the process, insert the biological indicator in a test pack
and place pack on the bottom shelf. Run test pack through a typical
cycle. On completion, forward test pack and monitor to appropriate
personnel for evaluation. Refer to current guidelines to conduct
routine biological monitoring.
3.2.2 Chemical Measure
(Bowie-Dick Tests)
The STERIS Dart
®
Testing Apparatus to Determine the Effectiveness
of Removing Air from a Chamber and the Bowie-Dick Test Pack both
use chemical indicators to document the removal of residual air from
a sample challenge load in a prevacuum sterilizer. These tests do
not apply to gravity or liquid cycles.
After exposure in a prevacuum test cycle, the test pack is opened,
chemical indicator examined, and conclusions drawn as to the
pattern of residual air, if any, that remained in the pack during the
sterilizing cycle. Any indication of a malfunction must be reported to
the supervisor. The sterilizer must not be used to run prevacuum
cycles until approved by supervisor.
Dart Testing Apparatus is designed to be used at a 132-134°C (270-
273°F) with an exposure time of 3.5 to 4 minutes. The Steraffirm
Bowie-Dick Test Packs are available for two cycles:
• 121°C (250°F) with 8 minute exposure time
• 132°C (270°F) with 3.5 minute exposure time
Refer to instructions for running the Bowie-Dick in S
ECTION 6.7, DART
AND BOWIE-DICK CYCLES.
A Bowie-Dick Test cycle is not a test for adequate exposure to heat
in terms of time-at-temperature.
WARNING – STERILITY
ASSURANCE HAZARD: Load
sterility may be compromised
if the biological or chemical
indicator, or vacuum leak test
indicates a potential problem.
If these indicators show a
potential problem, refer the
situation to a qualified service
technician before using the
sterilizer further.
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