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CPT Medical

What Are The Methods Of Sterilization?

Surgical equipments

Sterilization is a process of eradicating live microorganisms from substances. It is done to preserve things for a long time and kill germs. If something is not sterilized, it may cause infection to those who use it. Therefore, it should not be taken for granted. There are several methods of sterilization, including:

Heat sterilization

This is the most common type of sterilization because the heat used kills all microbes. The extent of sterilization is affected by the duration of heating and heat temperature. As the temperature goes up, the duration of heating goes up. The heat method of sterilization can be further divided into two:

Moist heat methods

Here, heat is applied through boiling and includes methods like pasteurization, using steam, and boiling. Boiling is done for metal devices such as surgical scissors, custom trays, and needles. The substances are boiled to kill any microbes. Pasteurization, on the other hand, is a method for heating milk to 60 or 72 degrees thrice or four times.

When using steam, the substances being sterilized are subjected to steam in autoclave steam heating equipment. The process uses temperatures of up to 115 degrees for an hour. It is the most common method for sterilizing drugs because it can kill the bacterial spores, which are inert bacterial forms.

Dry heat methods

Substances are subjected to flaming, incineration, hot air ovens, or radiation sterilization. In flaming, metallic devices such as needles or scalpels are placed over a flame for several minutes. The flame will kill all microbes directly. Incineration is used especially for inoculating the loops utilized in microbe cultures. The loop’s metallic end is burnt red hot on a flame, killing all microbes.

The radiation method involves the exposure of packed materials to radiation. There are two types of radiation: non-ionic and ionizing radiation sterilization. The former is safe to the person doing the procedure while the latter requires the operator to wear protective gear. The hot air method is ideal for dry materials such as glassware and powder. They are placed inside the racks of a hot air oven until sterilized.

Chemical sterilization

In this method, the items are subjected to sterilization through toxic gasses. When sterilizing heat sensitive liquids, you should use bacterial filters. Three types of filters are used in this type of sterilization:

  • Seitz filters – they are made from materials such as asbestos and are pad-like and thicker than a membrane filter. Seitz filters do not rupture during the process of filtration. However, the solution can end up being absorbed by the filter. An alternative to Seitz filters are sintered glass filters, which are made of glass and hence cannot absorb liquids. However, they are fragile and breakable.
  • Membrane filters – these thin filters are made of cellulose and can be used for online sterilization during injections. The membrane is placed between the needle and syringe. However, this type of filter can rupture easily causing improper sterilization.
  • Candle filters – they are made from clay such as diatomous mud, which has small pores made by algae. The filters have many lengthy pores that trap the microbes as they travel through the candle.

The type of filter that you choose depends on the substance that you want to sterilize. When using gas to sterilize, cost factors as well as chances of explosion should be considered. The gasses used are usually very toxic and should be used with caution. If you want to sterilize surgical instruments, the most effective methods are autoclave, boiling, and incineration.