In comparison to the autoclave or other moist heat sterilization methods, a hot air oven has a lower heat capacity and it's slower in killing microorganisms. It's not suitable to sterilize all equipment, like plastic wares and heat-sensitive materials.
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.
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).
An autoclave uses pressure and steam to sterilize the contents. It's quick and uses lower temps than air ovens. Hot air ovens use dry heat, high temperatures and longer times to achieve the same result. Both achieve the same result, but do it in very different ways.
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.
The two common steam-sterilizing temperatures are 121°C (250°F) and 132°C (270°F).
A laboratory hot air oven is widely used in scientific research, pharmaceutical industries, and microbiology labs for sterilization, drying, and heat treatment of glassware in various industries. It operates by circulating heated air to ensure uniform temperature distribution, removing moisture and contaminants.
By definition, a hot air oven is a sterilizing machine or device that is used to sterilize the equipment and some other materials using dry heat. It is also known as a forced-air circulating oven. The process of dry heat sterilization using a hot air oven was originally developed by Louis Pasteur.
Autoclaves are commonly used in healthcare settings to sterilize medical devices. The items to be sterilized are placed inside a pressure vessel, commonly referred to as the chamber. Three factors are critical to ensuring successful steam sterilization in an autoclave: time, temperature and steam quality.
Hot Air Oven are designed to generate heat with blower assisted air re-circulation inside the chamber at temperature from ambient+10°C to 150°C, 200°C or 250°C.
The disadvantage of autoclaves is that they are unsuitable for heat-sensitive objects and repeated exposure to high humidity and heat may dull sharp, fine cutting instruments, particularly high-grade carbon steel edges of scissors and scalpel blades.
With steam (moist-heat) sterilization, saturated moisture conditions elevated pressures, and elevated temperature (e.g., 104–138 °C) are optimal for sterilization. The lower the temperature, the longer the exposure; however, more materials tolerate lower temperatures.
121oC is necessary, because at 100oC (the boiling point of water under unadulterated atmospheric conditions) endospores are not killed and thus sterilization cannot be fully achieved. In fact, Geobacillus stearothermophilus is used as an indicator to confirm that a successful sterilization cycle was completed.
Hot air ovens use extremely high temperatures over several hours to destroy microorganisms and bacterial spores. The ovens use conduction to sterilize items by heating the outside surfaces of the item, which then absorbs the heat and moves it towards the center of the item.
Storage of Sterile Items
They should be stored in a closed cabinet and protected from moisture. As a general rule, packs wrapped in cloth or woven paper must be used within 1 month of autoclaving and sealed peel packs must be used within one year.
Hot Air Oven: Takes a longer time to achieve effective sterilization, usually between 1 to 2 hours, as dry heat is less efficient at penetrating materials compared to steam. Autoclave: Has a much faster sterilization cycle, typically between 15 to 30 minutes.
Common sterilization times are 170°C for 30 minutes, 160°C for 60 minutes, or 150°C for 150 minutes. Items are sterilized as heat penetrates from the outside in, destroying cell constituents. Quality controls like Browne's tubes and spore strips ensure proper sterilization.
o DO NOT AUTOCLAVE SEALED CONTAINERS OR BAGS.
However, prions, such as those associated with Creutzfeldt–Jakob disease, and some toxins released by certain bacteria, such as Cereulide, may not be destroyed by autoclaving at the typical 134 °C for three minutes or 121 °C for 15 minutes and instead should be immersed in sodium hydroxide (1M NaOH) and heated in a ...
PROHIBITED ITEMS: Autoclaves must not be used with the following: ▪ Corrosives (e.g., acids, bases, phenol, etc.), solvents (e.g., ethanol, methanol, chloroform), or radioactive materials: Contact EHS or review the EHS Program Manual, Section 5.2 - Waste Disposal Procedures for proper decontamination and disposal ...