Which of the following solutions is used in the autoclave for sterilization?

An autoclave is used in medical and laboratory settings to sterilize lab equipment and waste. Autoclave sterilization works by using heat to kill microorganisms such as bacteria and spores. The heat is delivered by pressurized steam. Pressurization allows the steam to reach the high temperatures that are required for sterilization.

According to Centers for Disease Control (CDC) Guidelines for Disinfection and Sterilization of Healthcare Facilities, pressurized steam is the most widely used and dependable method of sterilization. It’s nontoxic and inexpensive, it kills microbes and spores rapidly, and it quickly heats and penetrates fabrics.

According to manufacturer Tuttnauer, medical clinics and dental offices typically use tabletop autoclaves, which are about the size of a microwave oven, while hospitals use much larger units that can sterilize many instruments at once.

To work effectively, an autoclave must remove all the air in and around the object that’s being sterilized, forcing steam to penetrate its surfaces, according to Healthcare Purchasing News. There are two basic ways that an autoclave can remove the air and force in steam:

• Gravity displacement autoclaves, also called gravity autoclaves, inject steam into the autoclave chamber and then rely on that steam, which is heavier than air, to force the air to leave the chamber through the drain vent at the bottom, according to the CDC.
• Prevacuum or prevac autoclaves use a vacuum pump to remove air from the chamber before steam is admitted to it, which means that steam penetrates even porous objects almost instantly.

What Type of Autoclave Do I Need?

Gravity autoclaves have a simpler design and are recommended for most uses, according to manufacturer TOMY. They are suitable for common laboratory media including type I borosilicate glassware or other autoclavable labware, steel lab utensils, and biohazardous waste. On the other hand, prevac autoclaves are more effective at sterilizing objects that are large or porous, including wrapped objects such as surgical kits; objects made from high-density polyethylene, such as pipette tips and syringes; and animal cages and bedding.

Autoclaving is the most effective and reliable means of sterilizing laboratory materials. Autoclaving sterilizes material using saturated steam under pressure (“moist heat”). Due to the use of pressure, steam and high temperatures, there is significant risk for injury, so it's important for individuals to be properly trained on operational procedures.

Autoclaves may be used to sterilize equipment/products prior to use in an experiment or to render items non-infectious prior to disposal. The University of Iowa’s Biohazard Waste Guidelines states that cultures, plates, and vials containing pathogenic organisms must be autoclaved prior to disposal. The reason for autoclaving infectious waste is that it must be handled several times during transport; proper containment and treatment at the source reduces the potential for an accidental exposure. The necessary treatment to achieve sterility will vary in relation to the volume of material treated, its contamination level, moisture content and other factors.

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Autoclave Compatible and Incompatible Material 

The following are examples of compatible and incompatible materials. This is not an exhaustive list.

Important Notice: Autoclaving hazardous materials may generate toxic vapors or explosive environments.

Compatible Materials

Incompatible Materials

  Biological cultures and stocks

  Materials containing solvents, volatile or corrosive, or flammable chemicals

Culture dishes and related materials

Material contaminated with chemotherapeutic agents or cytotoxic drugs

Contaminated solid items (i.e. pipette tips, gloves, Petri dishes, etc.)

Material containing Bleach*

Discarded live (including attenuated) viruses/vaccines

Carcinogens or mutagens (i.e. ethidium bromide)

Polypropylene (PP) and polycarbonate (PC) plastics

Phenol and Trizol

Borosilicate glass

Polystyrene (PS), polyethylene (PE), and high-density polyethylene (HDPE) plastics

Stainless steel

Houshold glassware

* Neutralize waste containing bleach with equal amounts of 1% sodium thiosulfate in water prior to autoclaving

• Every autoclave and sterilizer should be inspected and serviced on a regular basis. This will help ensure the equipment is functioning properly.
• Each unit should have a standard operating procedure written in sufficient detail to ensure that operators will use the equipment properly; controls vary between brands, with each having unique loading characteristics, load-sizing requirements, and cycle setting and types. Principal Investigators and/or lab managers should ensure users are properly trained on the autoclave in use.
• Units should be tested regularly with a commercial preparation containing Geobacillus stearothermophilus spores (a biological indicator), in particular, any unit in a BSL3 facility.
• Tape indicators (autoclave tape) with heat sensitive, chemical indicators should be used in every autoclave load. Note: the indicators only verify that the autoclave has reached normal operating temperatures; they do not indicate that the contents were heated for the appropriate length of time or at the proper pressure. Therefore, tape indicators cannot be used to prove organisms are actually killed during an autoclave run.
• Keep detailed records on biological tests, recording thermometers, and service work performed on the unit.
• High density wastes or materials that insulate the agents from heat and steam penetration are not suitable for steam sterilization. Items that are covered with dirt or film require additional retention times. The importance of properly cleaning items to be sterilized cannot be over emphasized.
• Place all autoclaved infectious waste into red biohazard bags for disposal.
• An online training video was developed by Arizona State University that offers safety information, examples of waste to be autoclaved, and procedures for spore testing that may be helpful to any user. The video is available at: https://www.youtube.com/watch?v=rM_JTgLSKXk&feature=youtu.be
• Autoclaved waste can cause odors, the use of autoclave deodorizers may assist if there is a general problem in the area.

The following PPE should be used during loading and unloading:

• Standard laboratory clothing including long pants and closed-toed shoes
• Eye/face protection
• Gloves (including heat resistant gloves)
• Laboratory coat

The proper packaging and containment of infectious materials are crucial to achieve effective sterilization. The most frequent reason for sterilization failure is the lack of contact between the steam and microorganisms. Dry material should be separated from liquid material to achieve proper sterilization.

Which solution is used for autoclave?

Which solution is used for sterilization?

What chemicals are used in autoclave?

What liquid is used in an autoclave to sterilize equipment?