Sterilization holding cycle

If the degree of sterilization (Wf/Wo) and the temperature duringthe holding cycle are given, the holding time can be calculated. 

Many phases of an autoclave cycle may be controlled through pressure signals. Pumping down to preliminary vacuums continues until pressure signals isolate the pump and open a steam valve. The sterilization hold phase may also be controlled by pressure signals. The pressure at which the specified temperature was reached may be maintained within limits of pressure (and hence of tern-... 

Polyarylsulfones offer materials with good thermal-oxidative stability, solvent resistance, creep resistance, and good hydrolytic stability. Their low flammability and smoke evolution encourage their use in aircraft and transportation applications. They hold up to repeated steam sterilization cycles and are used in a wide variety of medical applications such as life support parts, autoclavable tray systems, and surgical and laboratory equipment. Blow-molded products include suction bottles, surgical hollow shapes, and tissue culture bottles. PPS has a number of automotive uses including as an injection-molded fuel line coimector and as part of the fuel filter system. 

The range of sterilization specifications calculable by these various approaches is summarized in Table 2. It is apparent that very brief sterilization specifications (on the order of 2-3 min holding time at 121°C) are obtainable when the microbiological contamination is completely characterized in terms of numbers and thermal resistances. In practice, such limits on hold times could be difficult to control precisely, are probably insignificant in terms of thermal lethality compared with heat-up and cool-down times, and could prove difficult to sell to regulators. Without complete thermal characterization of thermal resistances, specifications calculable by the bioburden approach are hardly significantly shorter than overkill specifications. Thus, it probably makes practical sense in most cases to choose only between overkill cycles for thermally resistant products and aseptic manufacture for heat-sensitive products. 

All flasks, solutions and other accessories that come into contact with the media solutions must be sterilized or purchased pre-sterilized. For sterilization, a high pressure steam autoclave (AMSCO 3021) was used with a liquid cycle that holds the contents at a temperature of 121°C/14 psi for 25 min. 

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