Sterilization is the process of destroy all microbial life forms that can contaminate materials and objects, such as viruses, bacteria, fungi and others, through the use of chemical or physical agents.
This process makes the reproduction of these organisms unable to take place, thus causing the so-called microbial death.
The intention of sterilization is that the probability of survival of the agent that can contaminate an organism is less than 1:1,000,000, and that object may be considered sterile.
The effectiveness of any sterilization process will depend on factors such as the type of method chosen, the nature of the material, type of contamination and conditions under which the final object was prepared.
As for human and veterinary medicine, sterilization is characterized as a surgical method that interrupts the ability of a living being to reproduce, making it sterile and infertile.
Generally, sterilization procedures in living beings are a permanent form of contraception, which is irreversible.
See more about Asepsis.
Types of sterilization
The sterilization of materials can be developed through different chemical and physical processes.
The most frequent alternative is to submit the object to be sterilized to high temperatures until the microorganisms die. However, there are other methods such as:
Steam Sterilization
The exposure of microorganisms to saturated and pressurized steam from an autoclave causes the so-called denaturation of enzymes and structural proteins. The temperature can vary inversely to the amount of water present in the process.
Dry heat sterilization
In dry heat sterilization, the primary objective is the oxidation of cell constituents. It also requires the use of very high temperatures in addition to very long exposure time. In its process there are steps such as buckling, incineration, infrared rays and the hot air oven.
Gas Sterilization
The active agent in the gas sterilization process can be ethylene oxide or another highly volatile substance that works as an alkalinizer for proteins such as DNA and RNA.
As it is considered highly flammable, this procedure should only be considered if no other sterilization procedure is possible.
Sterilization with ionizing radiation
As it is a sterilization method that uses low temperatures, ionizing radiation can be used in thermosensitive materials.
Some atoms have the property of emitting waves or particles according to the instability of their nuclei, thus changing the electric charge of the radiated material by electron displacement.
For industrial sterilization purposes, beta and gamma ray sources are used.
Sterilization and Disinfection
The process and care with the cleaning of materials used in the laboratory avoids contamination and problems with the results of the experiments. And the sterilization and disinfection of materials are the most basic processes to be carried out. However, both have some differences.
While the disinfection it is the process that eliminates a large portion of the microorganisms present on the surfaces of the equipment, using products such as chlorine, sodium hypochlorite and alcohol, the sterilization it works as a complement, being more effective in eliminating all life forms present in laboratory materials.
When performed correctly, sterilization eliminates all bacteria, fungi, viruses and spores.
See also the meaning of Disinfection.