Steam sterilizer temperature monitoring

List of parameters (Shelf-to-Shelf Temperature Uniformity, Steam Sterilization Study — Shelf Monitoring, Steam Sterilization Study — Chamber Monitoring — Last 15 minutes of Exposure, Steam Sterilization Study — Eg Minutes, Steam Sterilization — Biological Indicator Test Results, Leak Rate Test, Vacuum Pump Down Test) Acceptable Limits, and Study Results... 

Thermocouples obviously must be sufficiently durable for repeated use as temperature indicators in steam sterilization validation and monitoring. Copper-constantan wires coated with Teflon are a popular choice as thermocouple monitors, although several other types are available. 

The complexity of the sterile filtration operation and the CGMP regulations require the validation of sterilizing filter systems. The validation of a sterile filtration operation can be complex, with many operational parameters and their interactions needing to be identified, controlled, and predicted for each end product to demonstrate that sterility is adequately achieved by the filtration process. In the commonly used steam sterilization process, the heat parameters are identified and in-process controls specified such that a level of sterility assurance can be reproducibly obtained. In steam sterilization, the important parameter of heat, measured by temperature, can be accurately measured and continuously monitored to ensure the operational integrity of the autoclave however, unlike steam sterilization, filtration sterilization cannot be monitored on a continuous basis throughout the process. 

Process controls and monitoring typical for steam sterilization (e.g., time, temperature, and pressure). ... 

Steam sterilization processes are monitored for compliance with strict specifications of temperature, pressure, and time. Routine monitoring with biological indicators is not necessary. Indeed, any item of steam sterilizingequipment that is operating so erratically as to merit routine monitoring with biological indicators should be replaced. 

The WFI distribution system (storage tanks, circulation pumps, pipework) is steam sterilized. The sterilization cycle is controlled and monitored by temperature indicators located at critical points. 

The hot section (Fig. 5) is controlled by a cascade loop which is based on a selected pumping rate (150 gpm) and sterilization temperature set in the TIC. Changes in the feed temperature are monitored at TTl which will automatically override the steam supply to keep the temperature at set point. Steam flow rate is monitored (by FE) and flow is automatically compensated should a large drawdown of steam occur elsewhere in the plant. Temperature is recorded at the beginning and end of the hot section. The hot section should be well insulated and special care should be given to the pipe supports for expansion. (Instrumentation symbols used here and in Figs. 3, 5, 6 and 7, conform to the standard symbols of the Instrument Society of America.)... 

Academic texts on steam sterilization often state that routine control of steam sterilization processes should concentrate on the measurable detenninams of lethality, temperature and time. Temperature should be monitored at the coldest point, usually in the drain line, but if this is not the coldest spot there should be a floating probe at the coldest spot, or the relationship between the drain line and the coldest spot should have been well established and documented. A permanent record of the temperature throughout the sterilization cycle should be a compulsory feature of all production-scale autoclaves, and this should be inspected in detail for batch release. In practice this is not sufficient to confirm that sterilizing conditions have been attained. 

Chamber temperature should be controllable and monitored throughout all cycles. The temperature obtained in a load is a function of the initial product temperature and Its specific heat, the amount of steam injected, and the effectiveness of the insulation or the jacket at preventing heat loss. Temperature during the exposure phase of ethylene oxide sterilization cycles is not controlled by steam injection into the chamber as occurs in thermal sterilization. Loss of temperature may be compensated for by steam Injection into the jacket. The control probe is usually located within the chamber rather than within the jacket, and control of temperature is a good deal less fine than ini steam sterilizers because of the slower response through the jacket. Ethylene oxide sterilizers should be equipped with both jacket and chamber temperature indicators, and with chamber temperature recorders. Sterilizers should be specified with access... 

The fermentation process is operated under aseptic and optimum environmental conditions and ordinary temperature and pressure. In addition to the multicomponent culture broth, the concentration of each component contained in the culture broth is changed over the cultivation time. Therefore, heat resistance for steam sterilization and measurement specificity for the target compound are required for a monitoring system applied to fermentation process. 

Moist heat sterilization is achieved by exposure to saturated steam under pressure in a suitably designed chamber. In these circumstances there is an exact relationship between the steam temperature and pressure, but the pressure is used solely to obtain the temperature required and otherwise contribute nothing to the sterilization process. The time, temperature and pressure must be used to control and monitor the process. 

As further evidence of the modified polymer s excellent hemocompat-ibility, in vivo trials incorporating the polymer into a hemoperfusion device were conducted at the University of Cafifomia at Davis. A polycarbonate cartridge containing lOOmL of the polymer was steam autoclaved at 120°C for 45 min and flushed with 1L of sterile safine prior to use. Several times two healthy canines underwent 5 h of hemoperfusion at a flow rate of 200 mL/min. No adverse effects such as fever or hypotension were noted. Temperature, blood pressure, mixed venous oxygen saturation, and hematocrit were continuously monitored during the procedure and all remained unchanged throughout the procedure. 

Hot water (>82°G/180°F) or steam is an ideal sterilant. It has penetrative properties, works against all wine/juice microorganisms, is noncorrosive, and relatively inexpensive. Bottling line sterilization can be accomplished with steam or hot water. Where hot water is employed to sanitize lines, recommend minimal temperature X time requirements are >82° G (180°F) for more than 20 min. When steam is used to sterilize tanks, the recommendation is to continue until condensate from valves reaches >82° G for 20 min. In both cases, the temperature should be monitored at the furthest point from the steam source (i.e., the end of the line, fill spouts, etc.). The practice of dismantling valves, racking arms, and so on and immersion in containers of hot water may not yield the time and temperature relationships necessary for sanitization. 

For sterilization the jacket is heated by steam. Valves 4-6, 8, and 10 are closed and the pump 7 is off. Valve 11 is opened to drain the jacket. After a short period, valve 11 is closed and valve 12 is opened. Valve 1 is opened to let steam into the jacket. The condensate drains through the steam trap 13. The temperature and pressure of the circuit are monitored at TICl and PIl. Cooling is carried out by closing valves 12 and 1 valves 8 and 4 are opened. Cooling water enters the circuit at valve 4, Aows up the jacket and out to the cooling water return line (Fig. 21). All operations are generally automated for consistent and error-free condol. 

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