Sterilization of Meterials and Equipment

I. STERILIZATION OF MATERIALS AND EQUIPMENT Sterilization is a process to kill all organisms contained in an object (tool or material). Purpose of internal sterilization microbiology is deadly, inhibits growth and eliminates all microorganisms present on the tools and materials that will be used in a job to create an aseptic atmosphere. In general, sterilization can be carried out by 3 methods: mechanical, physical and or chemically. Mechanical sterilization includes using microfillter, physical is divided into 2 irradiation and heating, while chemical is to use chemicals (disinfectants). Materials, tools and work tables that will be used in practice at Microbiology laboratories must go through a sterilization stage first The aim is that the work is carried out aseptically or free from microbes unwanted contaminants. As for sterilization, which is often used in The basic practice of microbiology is physical sterilization by heating, which divided into dry sterilization and wet sterilization. A. Physical sterilization 1. Warm up a. Dry Sterilization (Dry Heat) Several methods that can be used in dry sterilization are: 1. Nurturing Burning is an activity of directly burning tools such as ose tip, tweezers tip, metal spatula tip. Flushing is done until the tools are glowing red. 2. Flaming (Licks of Fire) Tools such as glass objects, petri dishes containing media, mouths Erlenmeyer which contains media and a needle, simply do a flame or Pass the tool into a Bunsen flame. This means that these tools only experienced a flash of fire and did not glow. Image of sterilization with a lick 3. Hot Air Generally dry sterilization is carried out in this way, where the tool used is an oven. The temperature usually used is 160-1800C for 1-2 hours. Dry sterilization with an oven is good for dry tools made of glass, such as: petri dishes, test tubes, sample bottles, pipettes, syringes glass, tweezers, scissors, non-permeable materials such as glycerin, oil, vaseline, powder, and or anything else that does not become damaged, ignite, burn or evaporates at high temperatures. he penetration of heat into the material in this method is very slow, Therefore, during sterilization, it must be in a thin layer and in sufficient quantities small amount, must be protected in a closed container by wrapping or plug to prevent contamination after removing from the oven. For To ensure the effectiveness of the sterilization process, it is necessary to pay attention to the load (the number of tools used). put into the oven) so that there is enough room for the flow to move hot air. b. Wet Sterilization (Wet Heat) Wet sterilization can be done in several ways, including: 1. Flowing Steam This is sterilization using steam at a temperature of 1000C flowed into the sterilized object repeatedly (three to four times minutes) with an interval of 24 hours. Or sterilize with flowing steam This is also called multilevel sterilization or tyndalization. This method is introduced by John Tyndall (1820-1893). The advantage of this method is that it does not require special tools. However The disadvantage is that it takes a long time, in addition to the time interval between flows The flowing steam allows resistant or dormant (non-active) spores to become active again and become vegetative cells. This method is used for media gelatin, milk, and carbohydrates, because these ingredients will experience hydrolysis when a higher temperature or longer time is used. 2. Deliberation in Water Boiling is done to kill non-sporulating microorganisms. Boiling in boiling water or reaching a temperature of 1000C, only 5 minutes is usually enough to sterilize household equipment, as long as the water actually comes into direct contact with the tool, not only just the outside or surface but down to the inside. However Sterilization in this way can be carried out for a longer time, depending on the level of contamination of the equipment being sterilized. A sterile state that is not can be achieved by boiling in hot water for 1 hour and can be continued with steam flowing. 3. Pressurized Steam An autoclave is a tool used in sterilization using steam under pressure. In an autoclave the steam is in a saturated state, and increases pressure causes the temperature reached to be higher. This sterilization method uses a temperature of 1210C for 15-20 minutes with a pressure of 1 atm. Pressure larger ones will be needed at places higher than sea level. All the air in the autoclave must be removed to obtain the desired temperature (1210C). Tools and materials sterilized in this way will be passed through by hot steam during the sterilization process. So that the materials are sterilized in this way it must be permeable to hot steam and not be damaged at temperatures of 110-1210C. Moist heat is very effective for sterilizing materials and tool even at a temperature that is not too high, because when water vapor condenses on sterilized materials and tools, releasing 686 calories of heat per gram of water vapor at a temperature of 1210C. This method of sterilization is effective for all microorganisms, both vegetative and spores. Several things are the principles of sterilization using an autoclave are: 1). Sterilization relies on steam, so the air must be completely evacuated from the sterilizer. 2). All parts of the sterilized material must be thoroughly passed through by hot steam, so empty flasks and tubes should be placed with sleeping position so that air is not trapped at the bottom. 3). The ingredients that porous or liquid form must be permeable to vapor. 4). The temperature should reach 1210C and be maintained for 15-20 minutes. 2. Exposure Physical sterilization can also be done with UV light irradiation (ultraviolet). Usually safety cabinets will be equipped with useful UV lights sterilize the interior surfaces of the safety cabinet , or to prevent contamination during the process of lowering the temperature of new media or tools Remove from oven or autoclave before use. Apart from that, UV lights too can be installed in a room to sterilize the room. B. Chemical Sterilization Usually used disinfectant compounds include: 1). Great equipment using HCl, HgCl2, Formalin, Phenol, Chlorine and alcohol. 2). Environment by using pesticides and antiseptics. 3). Media with Na-Thiosulfate. Usually the most widely used is alcohol, good for sterilize tools, workers' hands or work tables. C. Mechanical Sterilization Mechanical sterilization using a highly porous filter small, usually in the range (0.22 - 0.45 microns), so that microbes are retained on the filter. This tool, known as a microfilter, works with centrifugation force or vacuum pump. Where in this sterilization: bacteria are retained filtered, the virus cannot be filtered, and is used for materials that are not resistant hot and volatile, such as vitamins, enzyme solutions and antibiotics. Types of microfilters: 1. Non-disposable filtration apparatus - Suctioned with a vacuum pump - Volume 20-1000 ml 2. Disposable filter cup units - Suctioned with a vacuum pump - Volume 15-1000 ml 3. Disposable filtration unit with storage bottle - Suctioned with a vacuum pump - Volume 15-1000 ml 4. Syringe filters - Pressed like a syringe - Volume 1-20 ml 5. Spin filters - Pressed with centrifugation force - Volume less than 1 ml