Disinfection and sterilization: agents and equipment

Disinfection and sterilization - many people think that these concepts mean the same thing. However, nothing could be more wrong! They define two processes that are different from each other and are characterized also by different effectiveness. What is used for disinfection and what for sterilization? Which of these processes is more effective in fight against viruses and bacteria?

Disinfection is one of the methods of decontamination, i.e. the destruction of microorganisms. In the process of disinfection, only the vegetative forms of microorganisms are destroyed - it does not eliminate bacterial spores and "slow" viruses. So, this is not a fully effective process. There is also high-level disinfection that also destroys tuberculosis, enteroviruses and some spore forms. It is mainly used in medical facilities.

Disinfection is more often related to usable surfaces, e.g. countertops or frequently used handrails or door handles. By entering part of the sterilization string, it is also the pre-autoclaving process. In addition to hospitals and other medical facilities, there is a legal obligation to use the decontamination sequence, including facilities such as beauty salons.

Sterilization is a process that destroys all living forms of microorganisms. Reusable tools and equipment which contacts with sterile tissues are sterilized. The sterilized tool is completely safe for the body. An effective sterilization process should be carried out in a steam autoclave.  We will receive a sterile product, provided that the materials for the sterilization will be prepared correctly, the appropriate sterilization method will be selected and the process itself will be carried out correctly, and the materials will be stored correctly after the process. There are many sterilization methods that differ in effectiveness. These are among others:

  • steam sterilization with hypertension,
  • sterilization with running water vapor,
  • dry hot air sterilization,
  • infrared radiation,
  • ethylene oxide sterilization,
  • formaldehyde sterilization,
  • peracetic acid sterilization. 

Disinfection - what do we use for it? 

Disinfection can be carried out using many different means. We distinguish thermal disinfection, which takes place using water or steam and appropriate pressure. It is used to disinfect underwear, dishes and sanitary equipment. Another type of this process is chemical-thermal disinfection, which is carried out on equipment sensitive to high temperature. The most popular type is chemical disinfection carried out using solutions of instant preparations with different properties. The choice of a proper agent depends on the type of disinfected surface and the toxicity of the preparation. The chemical compounds used here include:

  • chlorine compounds - they are effective against spore forms of bacteria, viruses and fungi. They are used for surface disinfection, water installations and clinical waste. Irritating to skin, mucous membranes and eyes. They can also damage some equipment;
  • phenolic compounds - they are high bactericidal, anti-tuberculosis and fungicidal activity. In concentration up to 5%, they can be used for disinfection of countertops and pre-disinfection before sterilization. They are not recommended for disinfecting equipment in contact with skin and mucous membranes, because they may be irritating to tissues;
  • aldehydes - they are one of the most effective chemical disinfectants. Formaldehyde exhibits high bactericidal, viricidal and fungicidal efficacy, however, due to its irritating properties, it is not used to disinfect usable surfaces;
  • peracetic acid - a highly effective agent with oxidizing properties. In the case of bacteria and fungi, it has an effective result after 5 minutes from its application. Harmless to the environment, however, can cause corrosion of components including of copper and steel;
  • hydrogen peroxide - a broad spectrum agent. Slightly toxic and not irritating;
  • alcohols - ethyl and isopropyl alcohol are particularly applicable in disinfection processes. They are effective after 10 seconds from application against lipophilic (e.g. influenza) and hydrophilic viruses. However, they do not destroy bacterial spores. They have their use in disinfecting the skin and usable surfaces. Most effective in concentrations between 60 and 90 percent. Below 50% they lose significantly in effectiveness;
  • iodophors - are effective against bacteria, viruses and fungi. They find their application in antiseptics and disinfection.

Other disinfection methods include filtration that eliminates microbes from heat-sensitive liquids and UV radiation. It is used for the decontamination of air and usable surfaces. Does not penetrate deep into solids and liquids. The length of the UV waves used in this process is from 210 to 328 nm - 254 nm is the most effective. Mercury lamps are used for this purpose. Thymine dimers are formed, and consequently bacteria and viruses’ DNA are damaged. UV radiation also does not remove spore forms.

The effectiveness of disinfection depends on many factors. It increases with the passage of time and concentration of the disinfectant, as well, as the temperature and humidity increase. The effect of using these preparations is a disinfected surface or device, but it is not yet sterile and completely safe. Only sterilizer/steam autoclave ensures 100% efficiency and allows to minimize the risk of infection with microbes that are dangerous to health. 

Note: UV sterilizer - myth 

Increasingly we hear about the device known as the UV sterilizer. UV sterilization, or actually UV disinfection, is focusing mainly on the elimination of microorganisms, including bacteria and fungi that may be on the surfaces of objects and in the air. The length of the UV waves used in this process is from 210 to 328 nm - 254 nm is the most effective. We wrote before that mercury lamps are used to this process. But again, even that the DNA of bacteria and viruses is damaged, it is not completely effective and safe and additionally it can cause many threats. 

The UV "sterilizer" primarily does not remove spore forms of bacteria. Therefore, we cannot talk about the full effectiveness of this process and about sterility. UV radiation, changing the structure of nucleic acids, works mainly on vegetative, spore forms and inactive microorganisms. So, this device does not provide full security. This is not class B sterilization, but lower S or N, depending on the radiation source used. So, this is a cheaper, ineffective alternative.

Also, the ultraviolet rays used in the UV sterilizer propagate linearly, so they do not reach all potentially infected places, and microbes can survive in "shaded" places. UV radiation, destroying mainly microorganisms in the air and on surfaces, can be treated only as a supplement of sterilization and a supporting method, for example in health care facilities, clinics, private offices and hospitals. Bactericidal UV lamps reduce the risk of droplet infection, but do not penetrate deep into solids and liquids. This means that we sterilized only air, which will never replace the effective sterilization of reusable items in autoclave. The UV sterilizer also has a very long operating time - up to 8 hours. It can be used between treatments for 20 minutes, but it still does not provide full effectiveness and safety. Such lamps are also harmful to humans - UV radiation can cause skin irritation and even lead to the development of skin cancers. We can talk about effective sterilization only, when we are using a top medical class B steam autoclave.

Ball sterilizer - myth 

The ball sterilizer was very popular way to sterilize in a beauty salons. It is a device filled with small glass balls. These balls heat up to 240 degrees, but this product is not fully effective, it should not be even called a sterilizer. It can be used only to disinfect metal tools. The tools are not fully inserted, some of them are always outside. After the heating process, the tools are also not stored correctly, as in a steam autoclave. Also, the "sterilization" process cannot be controlled.  It is worth knowing that research on the effectiveness of the operation of a ball sterilizer was already carried out in the 1980s. At that time, a preliminary statement was issued on the reasons for changes in the provisions regarding disinfection and sterilization - July 1988. It was provided by the California Council for Hairdressing and Cosmetology. It stated unequivocally that the sterilization process with such a device could not be called true sterilization. According to the Food and Drug Administration (FDA), a ball sterilizer may pose a potentially unjustified risk of illness as well as injury to a patient. All because it is not 100% suitable for proper sterilization - (Federal Register, volume 45, No. 251, December 30, 1980).  Unfortunately, after all, such devices are often selected and used in various wellness salons. All because of their low purchase price. However, the low cost of purchase should never be an indicator of the choice of equipment. The most important thing should be the health and safety of clients who benefit from the treatments and employees, who will work on sterilized instruments in a ball sterilizer.

Autoclave - the only effective way of sterilization 

Only the autoclave, i.e. steam sterilizer ensures 100% safety and effectiveness. High pressure steam sterilization takes place in this equipment. As a result of this process, all forms of bacteria and viruses, including spores, are destroyed in the autoclave. The autoclave is a mandatory equipment for dental and medical surgeries and is used also in places where procedures are performed, wherever there is or may be a break in the skin's continuity, including in hairdressers, beauty salons and tattoo studios. It can be used to sterilize reusable metal tools, masks (before disposal), bandages and other hygiene and dressing products. 

The instrument, which has been autoclaved, is sterile and completely safe for the customer. The European Commission has entered the autoclave as an official key tool to combat the ongoing pandemic. In the era of pandemic, autoclaves are used also to sterilize reusable masks, bandages, dressings and other equipment. Enbio autoclaves are B-class medical autoclaves - they have CE certificate, approving them as medical devices. All the devices are complying with the standard EN13060:2004 and Declaration of Conformity  Autoclave is a device that significantly facilitates work not only in beauty salons, tattoo studios or hair salons. Such equipment is used in medical facilities and hospitals around the world due to almost 100% killing rate of all germs or viruses. Its advantage is above all quiet, effective and fast work, no matter what tools it sterilizes. If a given beauty or hair salon uses a steam autoclave in its daily work, we can be sure that in such a place our health and safety are a priority issue.   

Bibliography:

  1. Guidance COVID-19: cleaning in non-healthcare settings: https://www.gov.uk/government/publications/covid-19-decontamination-in-non-healthcare-settings/covid-19-decontamination-in-non-healthcare-settings
  2. http://store.uni.com/catalogo/en-13060-2004?josso_back_to=http://store.uni.com/josso-security-check.php&josso_cmd=login_optional&josso_partnerapp_host=store.uni.com
  3. Main Methods of Sterilization | Organisms | Microbiology, Kiruthika S: https://www.biologydiscussion.com/microbiology-2/sterilization-methods/4-main-methods-of-sterilization-organisms-microbiology/84729
  4. Sterilization guidelines, by ICRC: https://icrcndresourcecentre.org/wp-content/uploads/2015/04/sterlization.pdf
  5. Cleaning and Disinfection procedure ICPr001, by Northamptonshire healthcare: https://www.nhft.nhs.uk/download.cfm?doc=docm93jijm4n1414
  6. Do Glass Bead Sterilizers Really Work? By NLS Staff: https://www.nailsmag.com/392791/do-glass-bead-sterilizers-really-work
  7. Quick Answer: Does UV Light Kill Fungus? https://mississaugaautoloan.com/qa/does-uv-light-kill-fungus.html