How to sterilize the tools in an autoclave? A comprehensive guide

Instrument sterilization consists of several stages, and requires appropriate accessories, apart from the main equipment – the autoclave. Find out what is needed to carry out the full decontamination process and how to complete it step by step, for the best level of efficiency and safety. 

What will you need for the decontamination process?

Protective gloves

Gloves are indispensable during the process of tool decontamination – for the manual cleaning, disinfection, packing the tools in pouches, and also for placing the tools in the autoclave. There are many types of gloves on the market. These include gloves made of a mixture of latex and neoprene, internally chlorinated, as well as nitrile rubber, which are characterized by greater durability. In the "dirty" area – the place for the decontamination stages prior to sterilization – it is recommended that the gloves used by the salon staff fulfill the relevant European standards, protecting against chemicals and against pricks/cuts. Even two gloves can be worn on top of each other. The most popular diagnostic gloves, used e.g. in hospitals, are not suitable for the decontamination process - they do not provide adequate protection due to the fact that they are too thin and short.

Submit the tools to the disinfection (thermal / chemical / manual) process

Disinfection is a necessary stage prior to proper instrument sterilization. All reusable tools should be washed and disinfected after their use. There are several types of disinfection:

  • manual, thermal - suitable for heat-resistant equipment (at a temperature from 60 to 95 degrees Celsius, depending on the duration of the process),
  • chemical – using chemical preparations,
  • chemical, thermal.

The process of preparing the material for sterilization may require multiple stages. The one-step process is suitable for the equipment that does not require disassembly, and the multi-step might be needed for the equipment that does require disassembly. The multi-stage process includes the pre-cleaning stage, which is performed manually or with a specific machine, a proper cleaning stage and disinfection. If we do not use a machine for disinfection, we should submit the tools to a disinfection bath.

Biological tests and chemical indicators

Biological and chemical indicators are essential to ensure that the sterilization processes are running properly. Chemical indicators are tests dedicated to the selected sterilization method, and biological indicators are ampoule and strip tests containing specially developed, resistant strains of bacteria intended for incubation. For example, biological tests of the SPORAL type contain spores of the bacteria Geobacillus stearothermophilus, Bacillus atrophaeus or Bacillus pumilus, depending on the type of sterilization used. The selected tests should be in accordance with the recommendations of the sterilizer manufacturer.

Protection packages

Another necessary element consists of protective packages / foil sleeves, commonly known as sterilization envelopes or pouches. All reusable devices must be sterilized in a package that protects them from dust, moisture and secondary contamination until use. Protective sleeves and bags should allow the sterilization agent to pass through and block external factors at the same time. All types of packaging must meet European safety standards. They concern, among others, pore diameter, tear strength, chloride and sulphate content, strength and width of the seal. Depending on the weight of sterilized instruments, the appropriate class of packaging should also be selected - I (for light sets), II, III (dedicated to medium-weight sets) or IV - for heavy sets and special applications.

Ultrasonic washer

The ultrasonic cleaner is one of the best tools for the cleaning and disinfection processes. Ultrasound cleaning helps to get rid of dirt in even hard-to-reach places, impossible to remove in a traditional way. It is a fast, effective and safe process, even for very fragile reusable tools. When choosing an ultrasonic cleaner, pay attention to its power and temperature at which the disinfection process is carried out - a 50-70 W washer will be suitable for beauty salons performing manicure / pedicure, but for more advanced treatments, the power of the washer should be much higher. The optimal temperature is below 60 degrees Celsius. It is also required to purchase a special liquid for cleaning and disinfecting tools in an ultrasonic cleaner, supporting the entire process. After the end of the process, the tools should be rinsed with demineralized water and dried.

Distilled water

Distilled water is essential for the proper disinfection and sterilization processes. Its use guarantees that there are no minerals in the water that could damage the sterilized tools or the autoclave. The water pump and solenoid valves in the autoclave are particularly sensitive to contamination.

Chemical preparations

Many types of chemical preparations are used for the disinfection process. The chemicals used include chlorine-based compounds, alcohols, aldehydes, peroxy compounds and phenol derivatives. Phenolic compounds are used for pre-disinfection, prior to actual disinfection and sterilization. In a concentration of up to 5%, they can be used for disinfection of countertops and for initial disinfection. They are not recommended for disinfecting any equipment that comes in contact with the skin and mucous membranes, as they can irritate tissues. Chlorine compounds are one of the most popular chemical preparations with fungicidal and bactericidal properties. However, they cause corrosion of metals and irritate the skin and mucous membranes. Alcohols are also used in the disinfection process, most often ethyl and isopropyl alcohol. However, their activity drops significantly when diluted below 50%. Disinfectant solutions should be used in accordance with their intended use. For surface disinfection, agents that are effective within 15 minutes are used, whereas solutions that operate over a longer period of time –  are applied to disinfect equipment that can be immersed in them.

Dryer

A suitable dryer can be very helpful in a properly prepared decontamination process. After cleaning and disinfecting the tools, dry them thoroughly with a disposable non-woven cloth or with a dryer, before placing them in the sterilizer. Drying is a mandatory process and should cover all, even hard-to-reach surfaces. Water droplets on instruments prevent an effective sterilization.

Preparation for washing hands

Washing hands is the basis of occupational hygiene. It is worth using high-class preparations that do not contain harmful compounds. They should not contain any allergenic factors that cause irritation and dry hands. They should be synthetic soaps, manufactured in sterile conditions. Remember to wash your hands thoroughly, at least for 30 seconds.

Preparation for sterilization

1. Cleaning and preparation of tools

The first stage of the decontamination process is to clean the tools and prepare them for further processes. This is a very important activity, because even microscopic biological traces may prevent the proper sterilization process. Be aware of all grooves and recesses that are difficult to access. This stage can be performed by hand washing with soft brushes, sprinkling, rinsing and ultrasonic cleaning in special washers.

2. Disinfection

The next stage of the tool preparation for sterilization is disinfection. Depending on the manufacturer's recommendations, we can talk about chemical, thermal or chemical-thermal disinfection. It can be carried out in a special machine or in a washer for disinfection. In the case of chemical disinfection, particular attention should be paid to the appropriate concentration of the disinfectant, in which the instruments should be completely immersed.

3. Drying

Before wrapping the tools in special protective packages, dry them thoroughly by hand (e.g. with paper towels) or with a dryer using dry, compressed air. If prepared manually, they should be dried immediately to prevent the multiplication of microorganisms. After thoroughly drying the tools, remember to maintain them as such with a specially designed agent.

4. Tool packaging

In order for the sterilization process to run properly, we should also remember to choose the right type of packaging. The packages or pouches should be arranged in the autoclave in accordance with the principle of foil to foil, paper to paper, to achieve the best efficiency of the sterilization process.  

How are the tools sterilized in an autoclave? 

1. Loading the sterilization chamber

There are a few basic rules to remember. First of all, heavy instruments should be placed at the bottom of the sterilization chamber, and lighter ones at higher levels. The minimum filling of the chamber should also not be less than 1/6 of its capacity. Please pay attention as well to the maximum acceptable load size and weight, as specified by the producer of the autoclave.

2. Autoclaving (selection of the appropriate program)

Only by following the manufacturer's instructions will you be able to carry out an effective sterilization process in an autoclave. This process should not damage or alter the properties of the sterilized instruments. Choose the settings that match the type of the tools you want to sterilize - if the equipment is smooth, without gouges, etc., a shorter program can be selected. Do not forget about distilled water necessary for sterilization.

3. End of sterilization

After the sterilization process is finished, remove the tools to let them cool down. Then, keeping them in their pouches, place them in the specific place where they should be stored. The packaging should include the date of sterilization or the expiry date and a description of the contents, in the case of non-transparent packaging. 

How to control the sterilization process? 

To ensure that the sterilization process is indeed effective, you should carry out regular autoclave checks. The control of the sterilization process, as previously mentioned, is carried out by means of physical, chemical (parameter tests) and biological (effectiveness control) tests. How often to check the sterilization process? When using a steam sterilizer - depending on the type: once a month, once a week or once a day, each time the equipment is repaired and when automatic measurement and recording of critical parameters is not available.  

Proven practices - how to improve the sterilization process

  • The instructions for using the sterilizer must be read. Action in accordance with its instructions is required. This means that the load on the batch cannot be exceeded.
  • Autoclave manufacturers usually state how many packages will fit in the sterilizer - but it is the weight of the tools as well which can determine whether or not we can add more tools in the chamber.
  • The time of disinfection of tools – cosmetic and medical – depends on the disinfectant used. Application details are always listed on the leaflet which comes with the disinfection product.
  • Please remember that the instruments placed in the autoclave in pouches should be perfectly dry.