illustrates the minimum exposure times in steam sterilization for various types of items
in both the vacuum and gravity-displacement sterilizers.
d. Phase 4. Phase four is the drying and cooling phase. In this phase, the
steam inside the chamber is quickly removed so that it will not condense and wet the
packs. Filtered air is introduced into the chamber; the door is opened slightly to let the
vapor escape. Minimum drying time is 15 to 20 minutes. Items are removed after
drying time and allowed to cool. Never place freshly sterilized packages on cold
surfaces such as metal table tops since sweating will occur forming pools of water
which may be absorbed by the dry goods and contaminate the packages.
e. Phase 5. Phase five is called the testing phase. It is in this phase that the
sterilization process is checked for failure. For steam sterilization there are four types of
controls, which monitor the sterilization process.
(1) Mechanical controls. A time-temperature chart should be maintained on
each sterilizer and each cycle recorded on the chart. This chart is maintained as part of
the sterilizer load record. Figure 3-17 illustrates a sample-recording chart on a steam
sterilizer. This chart must be checked after each sterilization cycle to ensure that the
correct time and temperature standards have been accomplished in the cycle.
Figure 3-17. Prevacuum, high-temperature steam sterilizer (exterior view)
and time-temperature chart.