Sterilization pure steam

The relationship between temperature and pressure holds true only in the presence of pure steam adulteration with air contributes to a partial pressure but not to the temperature of the steam. Thus, in the presence of air the temperature achieved will reflect the contribution made by the steam and will be lower than that normally attributed to the total pressure recorded. Addition of further steam will raise the temperature but residual air surrounding articles may delay heat penetration or, if a large amount of air is present, it may collect at the bottom of the sterilizer, completely altering the temperature profile of the sterilizer chamber. It is for these reasons that efficient air removal is a major aim in the design and operation of a boiler-fed steam sterilizer. 

The drying chamber is rectangular in shape and is equipped with a door. It is vacuum- and pressure-resistant and designed for the freeze-drying process and sterilization with pure steam at an overpressure of (provide value) bar corresponding to (provide temperature in °C). 

Regarding microbiological results, for pure steam and water for injection, it is expected that they be essentially sterile. Because sampling frequently is performed in nonsterile areas and is not tmly aseptic, occasional low-level counts due to sampling errors may occur. Agency policy is that less than 5 CFUs/100 ml is an acceptable action limit. 

Steam sterilization is the method mostly used to sterilize freeze-dryers. High-quality, ultra-pure steam (water for injection standard USP XXII or PhEur equivalent) is used to achieve a minimum exposure of 121 °C for 30 min or the equivalent temperature-time combination for effective sterilization (Table 2.4.1). This method is easy to validate and is recommended by regulatory authorities as being reliable. The definition of sterilization is a validated process used to render a product surface free of all forms of viable micro-organisms (EN 556-1 2001). According to the authorities, a product or surface is only sterile when a validated sterilization process has been applied (EN 550, EN 552, EN 554, EN ISO 14160 and EN ISO 14937). 

Because pure steam is corrosive, Serail manufactures the chamber, condenser, shelves, coils, and all process piping in 316 L stainless steel. The system is designed to reduce the time of sterilization by fast cooling and inside dry vacuum of the trap and the chamber. The sterilization will take 5H2O. 

Moist-heat sterilization is achieved when a suitable combination of temperature and humidity can be introduced (or indirectly generated) at the level of the micro-organisms to be inactivated. The classic way to achieve this is by means of pressurized saturated steam at the temperature of 121°C (250°F). However, other sterilizing media (e.g., superheated water or a steam-air mixture) are also frequently used to obviate certain problems that pure steam may pose. Sometimes the load is rotated inside the chamber of the sterilizer to achieve particular results. 

Performance Qualification (PQ) verifies the performance of critical utility systems or processes. Critical utility systems such as WFI and Pure Steam are challenged throughout proposed operating ranges for extended periods of time, while an extensive program of quality monitoring is performed. Critical processes such as sterilization of components are challenged three (3) consecutive times under worst-case conditions. 

Figure 20 Principle of a venting filter for in situ integrity tests. The integrity tests are carried out following the water intrusion method 1, primary filter with an 0.22 pm cartridge 2, secondary filter with an 0.22 pm cartridge installed as a backup filter, sterilized independently of the filter 1 3, test liquid reservoir (WFI) with heater 4, inlet valve for test liquid (WFI) 5, pure steam inlet 6, filtered air (5 bar absolute) 7, venting gas (1060 mbar) 8, drain line with valves 9, to water ring pump (WRP) 10, to condenser 11, to chamber 12, sanitary valves 13, temperature sensors.

Comparison of evolved 14CO from four sterile and non-sterile soils 60 days after treatment with MSMA-l2tC showed that from 1.7 to 10.0% of the MSMA-14C was degraded in non-sterile soil, as compared with 0.7% in steam-sterilized controls. Four soil micro-organisms isolated in pure culture degraded... 

For porous and equipment loads, the steam comes into direct contact with the contaminating microorganisms on the materials being sterilized and there is no intermediary in the transfer of heat. The energy content of steam is defined by its latent heat. If the steam is pure in the sense that it contains neither entrained gas nor moisture, an amount of energy defined by its latent heat at the pressure of the steam will be transferred to the micro-organisms by condensation on their surfaces. 

Current pharmaceutical production practice uses substantially three moist-heat sterilization processes 1) pressurized saturated steam 2) superheated water and 3) steam-air mixture. Process 1 is the traditional multipurpose process, which obviously uses pure pressurized saturated steam as sterilizing medium. Processes 2 and 3 are so-called counterpressure processes they were introduced in pharmaceutical production practice approximately 20 years ago and, respectively, use a spray superheated water and a homogeneous... 

This is certainly the most widely used and most versatile moist-heat sterilization method. Accordingly, it is widely used not only for sterilization of pharmaceutical products but also for laboratory and hospital sterilization and for the treatment of medical devices. Nonetheless, it has significant limitations, especially in pharmaceutical use, which are described later. The sterilizing medium is obviously pure pressurized saturated steam. The word saturated means that the steam is in thermodynamic equilibrium with its liquid form (water) at the temperature being considered. 

When a container in the conditions noted earlier is sterilized in a conventional autoclave that operates with pure saturated steam, during sterilization a considerable overpressure with respect to the pressure inside the autoclave chamber is generated in the container. This is clearly attributable to the fact that the air (or gas) that was present at filling has remained in the container, whereas the air was eliminated from the autoclave chamber at the beginning of the process. Fig. 4 schematically explains the phenomenon in ideal conditions, i.e., considering air a perfect gas. 

These conditions therefore prohibit the use of traditional pure saturated steam autoclaves to sterilize solutions contained in a wide variety of containers such as... 

Thermal damage to biological systems is caused by absorption of heat energy. Well-controlled laboratory studies show that when pure cultures of microorganisms are held in saturated steam at a constant sterilizing temperature there arc linear relationships between the logarithm of the number of survivors and the time of exposure (exponential inactivation). 

This trouble can be checked by the addition of a large amount of pure culture of acetic bacteria. Steam and hot water sterilization of equipment is also practiced as a preventive measure. 

Fungi Perfecti PO Box 7634 Olympia. Wa. 98507 Phone 360426-9292 Fax 360-426-9377 HomePage WWW.fungi.com Products include micron filters laminar flow hoods sterile and room supplies pressure cookers steam boilers cultures sterile and growing room instruments pure cultures and spawn. Write for free brochure or include 4.50 for our fully illustrated catalogue. International orders welcomed. 

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