Hot air oven sterilizes objects such as glassware (test tubes, flasks, and pipettes), metal instruments (blades, scissors), powders (sulfadiazine, starch, zinc oxide), materials that have oil and glass test tubes.
Medical devices are sterilized in a variety of ways including using moist heat (steam), dry heat, radiation, ethylene oxide (EtO) gas, vaporized hydrogen peroxide, and other sterilization methods (for example, chlorine dioxide gas, vaporized peracetic acid, and nitrogen dioxide).
Sterilization of nutrient media is usually done using this process. Dry Heat (Hot Air Oven): The process involves heating at 160 ̊Cfor 2 hours or at 170 ̊Cfor 1 hour. It is used for glassware, metal and objects that will not melt.
As a general rule of thumb, you CANNOT autoclave materials that are contaminated with solvents, radioactive materials, volatile or corrosive chemicals, or items that contain mutagens, carcinogens, or teratogens.
Hot air ovens are laboratory testing equipment that are used to sterilise materials such as glassware, chemicals, and sealed containers. They are also used for drying, baking, curing, and heat-treating various substances.
Oven Method Sterilization
Preheat your oven to 275 degrees. Wash each canning jar or mason jar and lid with hot soapy water then rinse but don't dry them. Place each clean jar on a baking tray and place in the oven for 10 minutes. Soak the lids in boiling water for five minutes.
1) Ensure that the fan is in working condition during the operation. 2) Do not spill any chemical or water on the tray of oven. 3) Tong should be use to place/remove the glassware or any material from the oven. 4) Ensure that the Exhaust blower is ON before starting the oven.
Borosilicate and quartz are the recommended types of glassware in professional laboratories as they can withstand high temperatures and pressure, both necessary for efficient sterilization.
Examples of items that aren't sterilized in a hot air oven are surgical dressings, rubber items, or plastic material. Hot air ovens use extremely high temperatures over several hours to destroy microorganisms and bacterial spores.
Dry heat sterilization is usually reserved for items that cannot get wet, like powders, paper wrapped products, oils, and petroleum products. Glassware and metal are also often sterilized using this method.
Radiation kills germs that can cause disease and neutralizes other harmful organisms. Sterilization with ionizing radiation inactivates microorganisms very efficiently and, when used for product wrapping, ensures that healthcare products are safe and can be relied upon.
Hot air oven sterilizes objects such as glassware (test tubes, flasks, and pipettes), metal instruments (blades, scissors), powders (sulfadiazine, starch, zinc oxide), materials that have oil and glass test tubes.
Set the oven to its steam cleaning mode and run at 200°C for 25 minutes. Open the door and wipe the inner surfaces with a damp sponge or cloth, using warm water and washing up liquid. Note: Ensure you're wearing protective clothing and gloves to prevent any accidents or injuries.
The temperature and time for a hot air oven can vary based on the procedure. For sterilization, general settings are 170 degrees Celsius for 30 minutes, 160 degrees Celsius for 60 minutes, or 150 degrees Celsius for 150 minutes to eliminate microbes.
Applications of Hot Air Oven
It is used for sterilization of laboratory equipment such as glassware (flasks, pipettes, Petri-plates, and test tubes), culture media, metal items (forceps, spatula, scalpel, scissors), non-volatile compounds (zinc and starch powder, sulfonamide), and other materials that contain oils.
Hot-air is increasingly deployed in industrial processes. Typical applications include activating, heating, curing, melting, shrinking, welding, sterilizing, drying and warming to name a few.
Glassware can be placed in metal tray and finally in the hot air oven. All these can be heated at 160°C - 1 70°C for 2-4 hours. These are then removed from the oven and cooled. Paper or cotton should not be kept directly in the oven as these may be charred.
Medical devices that have contact with sterile body tissues or fluids are considered critical items. These items should be sterile when used because any microbial contamination could result in disease transmission. Such items include surgical instruments, biopsy forceps, and implanted medical devices.
An autoclave is a machine that uses steam under pressure to kill harmful bacteria, viruses, fungi, and spores on items that are placed inside a pressure vessel. The items are heated to an appropriate sterilization temperature for a given amount of time.
With that said, there are three main types of sterilization methods common within the scientific community today. They are steam, dry heat, and ethylene oxide (EtO) sterilization.