Wet Heat Sterilization

WET HEAT STERILIZATION Introduction Sterilizationis a process or activity of freeing a material or object from all forms of life. Sterilization can be carried out depending on the material or equipment to be sterilized. TYPES OF STERILIZATION In principle, sterilization can be done in 3 ways, namely mechanical methods, physical methods and chemical methods. 1.Mechanical sterilization (filtration)use a filter with very small pores (0.22 microns or 0.45 microns) so that microbes are retained on the filter. This process is intended for sterilization of heat-sensitive materials, for example enzyme solutions and temperature. 2.Physical sterilizationcan be done by heating and irradiation. a. Warmup 1) Burning (with direct fire): burning the tool in direct fire, examples of tools: inoculum needle (ose needle), tweezers, L rod. 2) Dry heat: sterilization in an oven at approximately 60-180 °C. Dry heat sterilization is suitable for instruments made of glass, for example Erlenmeyer, test tubes, crucibles. 3) Hot water steam: this concept is similar to steaming. Materials that contain water are more appropriate to use this method to avoid dehydration. 4) Pressurized hot water steam: using an autoclave. b. Irradiation with Ultra Violet (UV) UV light can also be used for the sterilization process, for example to kill microbes that stick to the interior surface of the Safety Cabinet by shining it with a UV lamp. c. Chemical sterilizationusually use disinfectant compounds, including empera. d. Sterilization with Hot Air Sterilization using this method is usually used for glass equipment, such as Petri dishes, measuring pipettes and Erlenmyer flasks. Glassware that is sterilized with hot air will not cause condensation so there are no drops of water (dew) in the glassware. AUTOCLAVE I. Definition: An autoclave is a tool for sterilizing various kinds of tools and materials used in microbiology using pressurized hot water steam. The pressure used is generally 15 Psi or around 2 atm and a temperature of 121 °C, 250 °C. So, the pressure acting on the entire surface of the object is 15 pounds per inch2 (15 Psi = 15 pounds per square inch). The duration of sterilization is usually 15 minutes for 121 °C. Autoclaves are made from materials and construction that is strong enough so that they can withstand high pressure and are safe for use. Used for sterilization of culture media, tools and for destruction of culture media. III. How to use the tool: 1. Fill enough water into the vessel 2. Install the heater 3. Put the tools/materials to be sterilized or destroyed into a vessel on a metal plate/rack with holes, then autoclave and lock/screw the lid firmly. 4. Open the valve / safety valve until all the air in the vessel is expelled. 5. Close the safety valve and leave for a few moments until the desired temperature and pressure are reached. 6. Note the time and wait as long as the desired heating time. 7. Turn off the heater, let the temperature drop while opening the safety valve so that the pressure in the vessel drops. 8. Afteropened.