c. Processing Sequence. The processing sequence for gas sterilization is:
Items are loaded.
Vacuum is created.
Additional moisture is added.
Gas is admitted.
Temperature, pressure, and humidity are maintained.
Exposure period is timed.
Gas is exhausted.
Air is admitted through bacteria-retentive filter.
d. Validity of Ethylene Oxide Sterilization. The effectiveness in EO sterilization depends
upon gas concentration, temperature, humidity, and packaging barriers. Table 3-4
illustrates the conditions for EO sterilization.
Table 3-4. Conditions required for sterilization with ethylene oxide mixtures.
e. Controls for Ethylene Oxide Gas Sterilization. Ethylene oxide gas
sterilization has mechanical, physical, and chemical controls just as steam sterilization
does. The biological control spore strip for ethylene oxide gas contains Bacillus subtilis
and must be used for every load every day. Chemical indicators are similar to those
used for steam sterilization but the color changes for gas rather than steam. The