The terms “tiệt khuẩn” and “tiệt trùng” (sterilization) originate from the Latin word “sterilis,” meaning infertile or barren. It means the complete destruction of all microorganisms, spores, viruses, viroids, and spore-forming microorganisms. Sterilization can be achieved using sterilants or certain physical agents. In microbiology laboratories, sterilization is a crucial measure when isolating, culturing, and preserving pure bacterial strains.
So, what exactly is “tiệt khuẩn,” and what is “tiệt trùng,” to differentiate them from disinfection, and what are the principles of disinfection and sterilization?
In the field of management and hygiene inspection in hospitals, restaurants, or laboratories, many find it challenging due to the abundance of technical terms. However, these terms are quite similar because the Vietnamese language is very rich.
Today, MIG will help those in microbiology or industrial hygiene better understand “Tiệt khuẩn” (Disinfection) and “Tiệt trùng” (Sterilization).
Terms: Sterilization, Disinfection
1. What is Sterilization (“Tiệt khuẩn,” “Tiệt trùng”)?
Sterilization (“Tiệt trùng” or “tiệt khuẩn”) is a method of completely destroying all living organisms, including vegetative microorganisms and microbial spores.
2. Disinfection (“Khử khuẩn,” “Khử trùng”)
Disinfection (“Khử khuẩn”) is a method used to kill microorganisms on objects or on the body to a safe level that does not endanger health. Disinfection services will not completely eliminate microbial spores.
Disinfection (“Khử trùng”) needs to achieve the irreversible inactivation of pathogens. It plays an important role when disease-causing agents can exist in many places where sterilization is difficult to implement for economic reasons, making widespread practical application challenging.
Currently, disinfection (“khử khuẩn” or “khử trùng”) has two methods: physical and chemical. Many chemicals are used to prepare liquid solutions as disinfectants.
Substances used to kill microorganisms on the skin and mucous membranes of the human or animal body without damaging body tissues are called antiseptics. These chemicals are less toxic to the body and are usually used at low concentrations.
Thus, a chemical can be used as a disinfectant solution or as an antiseptic depending on the purpose and concentration of use. For example, phenol at a concentration of 2-5% will be used as a disinfectant, while using a concentration 100 to 1000 times lower will make it an antiseptic.
Technical Measures and Principles of Disinfection and Sterilization:
1 Technical Measures for Sterilization:
To kill all microorganisms during sterilization, the most difficult task is to eliminate spores. The most commonly used methods are temperature, high-energy radiation, and ethylene oxide. These methods must ensure the destruction of microorganisms both externally and internally.
1.1 Sterilization Method Using Temperature
Sterilization with dry hot air involves using heated air for sterilization. There are two main sterilization methods using this approach: burning iron tools with alcohol and using a drying oven.
Burning steel tools with alcohol: This method provides very thorough and rapid sterilization but is rarely used due to the risk of damaging the instruments.
A sterilization drying oven is a rectangular cabinet with a thick insulated shell, capable of withstanding high pressure and maintaining a high temperature of 170-180 degrees Celsius for 1 hour. Microorganisms and spores are completely destroyed, and cotton and paper turn brown. This method is often applied to glass, metal, or ceramic items.
1.2 Sterilization with High-Pressure Steam
This is a method of killing microorganisms using high-pressure, saturated steam at temperatures above 100 degrees Celsius. When sterilizing objects contaminated with microorganisms, it is usually necessary to maintain a temperature of around 120 degrees Celsius at 1 atmosphere for 30 minutes, or 134 degrees Celsius for 15 minutes.
There are two ways to implement this sterilization method: boiling and using a boiling pot.
Boiling: This method cannot achieve absolute sterilization because the temperature is not high enough to kill some types of spores.
Using a boiling pot: This is the operating principle of an autoclave or steam sterilizer. The structure of this sterilizer includes a boiling pot: the lower compartment is filled with water, and the upper compartment is used to arrange instruments. This method can kill all spores because the temperature is very high, but it is difficult to control the temperature level, and only a small batch of instruments can be sterilized at a time.
1.3 Gamma Ray Method
This method uses high-energy ionizing radiation to destroy microorganisms.
This method is used for instruments and bandages in pre-packaged bags; to sterilize catgut and instruments sensitive to ethylene oxide or heat reactions such as catheters and grafts.
1.4 Sterilization Method Using Ethylene Oxide and Formaldehyde
This method uses ethylene oxide to kill microorganisms. However, because it is a very toxic substance, extreme caution and explosion prevention measures are necessary during its use.
1.5 Sterile Filtration Method
This method is used to sterilize air or liquid biological products where temperature methods or other sterilization methods cannot be used.
This sterilization measure often has many uncertain factors unlike physical measures. It is applied to heat-sensitive solutions, vaccines, serum products, etc.
2. Technical Measures for Disinfection:
2.1 Physical Disinfection Measures
Using hot steam at 80-100 degrees Celsius to disinfect and kill vegetative bacterial cells within a few minutes. Applied to clothing, patient utensils, pasteurized milk, or beverages.
Using ultraviolet (UV) rays, which are electromagnetic waves with wavelengths of 13.6-400 nm, to kill most bacteria. It does not kill fungal spores and bacterial spores, so it is often used to disinfect clean water and air, and to disinfect operating rooms, bacterial culture rooms, etc.
2.2 Chemical Measures
Using chemicals as disinfectants such as: soap, phenol and its derivatives, halogen compounds, heavy metal salts, alcohols, aldehydes, dyes, acids, and bases… to disinfect workplaces, laboratories, and to disinfect utensils and laboratory equipment…
Thus, disinfection (“khử khuẩn,” “khử trùng”) differs from sterilization (“tiệt trùng,” “tiệt khuẩn”). The appropriate method should be chosen based on the intended use and the materials being treated. For consultation on disinfection or sterilization tools or chemicals, please contact MIGCO for support and answers.
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