Bacteria and their spores are killed quickly, but fungal spores are only moderately sensitive to radiation.
Ionising radiation X ray, gamma radiation is used to sterilise food and other compact materials. Chemical means may also be applied. Ethylene oxide is used to sterilize food, plastics, glassware, and other equipment. Sterilisers may be batch or continuous by operated.
This results in a sterilised product with minimal heat damage to the product properties. UHT treatment is only possible in flow-through equipment. The product is thus sterilised before it is transferred to pre-sterilised containers in a sterile atmosphere. This requires aseptic processing.
For UHT treatment, indirect heating in plate and frame or tubular heat exchangers is applied. Jessamyn Stanley. Why We Swim Bonnie Tsui.
Related Audiobooks Free with a 30 day trial from Scribd. Pamela Peeke, M. Bunsen burner- for sterilizing bacteriological loops, knives, blades. Incineration 2. Red heat 3. Flaming 4. Hot air oven 5 6. Dry saturated steam — Autoclaving 2. Hot water below boiling point 4. Here substances are boiled to sterilize them.
If the sieve is blocked with debris, a layer of air may form at the bottom of the autoclave, preventing efficient 14 The chamber is closed tightly the steam keeps on filling into it and the pressure gradually increases. By increasing the temperature, the time for sterilizing is further reduced.
Can not be used for items that are lacking water. Generally used in irradiation of air in certain areas eg. Operating Rooms and T. Gamma radiation: Source Cobalt60 has greater energy than U.
Used mainly in industrial facilities e. A mercury lamp giving peak emission at nm is the suitable source of UV light in this region. Pathogens and microorganisms are destroyed when a thin layer of water is passed under the lamps water purifiers.
The material used mostly is unglazed porcelain, asbestos or other similar materials 22 The rate of regret after hysteroscopic tubal sterilization has never been evaluated. Patients with a medical indication for tubal sterilization or patients with an obturation of hydrosalpinx before in vitro fertilization were excluded.
A specific questionnaire to assess patients regret was sent by post to all patients. During the study period, hysteroscopic sterilizations were performed. The average age of patients at the procedure was Mean follow after sterilization was 43 months [ Seventeen of patients 5. Seven women out of 2. The process involves the use of formalin, which is vaporized into a formaldehyde gas that is admitted into the sterilization chamber. The sterilization cycle consists of a series of stages that include an initial vacuum to remove air from the chamber and load, followed by steam admission to the chamber with the vacuum pump running to purge the chamber of air and to heat the load, followed by a series of pulses of formaldehyde gas, followed by steam.
Formaldehyde is removed from the sterilizer and load by repeated alternate evacuations and flushing with steam and air. This system has some advantages, e. Low-temperature steam formaldehyde sterilization has been found effective against vegetative bacteria, mycobacteria, B. Formaldehyde vapor cabinets also may be used in healthcare facilities to sterilize heat-sensitive medical equipment Commonly, there is no circulation of formaldehyde and no temperature and humidity controls.
The release of gas from paraformaldehyde tablets placed on the lower tray is slow and produces a low partial pressure of gas. The microbicidal quality of this procedure is unknown Studies indicate that formaldehyde is a mutagen and a potential human carcinogen, and OSHA regulates formaldehyde. The permissible exposure limit for formaldehyde in work areas is 0. As with the ETO standard, the formaldehyde standard requires that the employer conduct initial monitoring to identify employees who are exposed to formaldehyde at or above the action level or STEL.
If this exposure level is maintained, employers may discontinue exposure monitoring until there is a change that could affect exposure levels or an employee reports formaldehyde-related signs and symptoms , The formaldehyde steam sterilization system has not been FDA cleared for use in healthcare facilities. A gaseous chlorine dioxide system for sterilization of healthcare products was developed in the late s , , Chlorine dioxide is not mutagenic or carcinogenic in humans.
As the chlorine dioxide concentration increases, the time required to achieve sterilization becomes progressively shorter. Currently, no gaseous chlorine dioxide system is FDA cleared. No vaporized peracetic acid system is FDA cleared. An infrared radiation prototype sterilizer was investigated and found to destroy B.
Some of the possible advantages of infrared technology include short cycle time, low energy consumption, no cycle residuals, and no toxicologic or environmental effects. This may provide an alternative technology for sterilization of selected heat-resistant instruments but there are no FDA-cleared systems for use in healthcare facilities The other sterilization technologies mentioned above may be used for sterilization of critical medical items if cleared by the FDA and ideally, the microbicidal effectiveness of the technology has been published in the scientific literature.
The selection and use of disinfectants, chemical sterilants and sterilization processes in the healthcare field is dynamic, and products may become available that are not in existence when this guideline was written. As newer disinfectants and sterilization processes become available, persons or committees responsible for selecting disinfectants and sterilization processes should be guided by products cleared by FDA and EPA as well as information in the scientific literature.
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