THE 3 MAIN STERILIZATION METHODS - MEDICINE - 2025

The sterilization methods are procedures by which it seeks to achieve microbial destruction objects. This means that it seeks to obtain an object free of microorganisms, reducing its viability.

Each of the methods must be applied according to the object or substance to be sterilized. The oldest sterilization process is heat, and today it is the most widely used in food, medicine, pharmaceutical industry and surgery.

Steam autoclave. Method mostly used in the sterilization of medical instruments.

Sterilization methods most used in medicine

In the medical and pharmaceutical industries, sterilization is necessary on a daily basis to promote health and eliminate the risk of contamination.

There are several different types of sterilization, all of which require that the temperature, gases, humidity, and pressure levels used be precisely controlled to ensure validity and effectiveness. These types of sterilization methods can be classified as follows:

1.-Physical methods (involving heat and radiation)

The heat

In this type of method are the procedures with humid heat called steam and dry heat, also called depyrogenation.

In the first case, sterilization occurs by denaturation and coagulation of proteins, while in the dry heat process, the desiccation of the cell occurs.

• Steam - Steam sterilization, invented in 1880, is primarily used for glassware, surgical instruments, and medical waste.
• Depyrogenation: used in products that can degrade when exposed to steam or moisture, but can withstand high temperatures.

Metal instruments, needles, and petroleum products are often sterilized in this way. All of these types have their advantages and disadvantages, but they are all equal in importance to the success of a medical facility.

Radiation

It is carried out at elevated ambient temperatures and at normal atmospheric pressure, applying gamma rays (ionizing radiation).

In practice, gamma ray sterilization can be used for objects containing semiconductor devices susceptible to steam damage.

In the case of non-ionizing radiation, a longer wavelength and lower energy are used, so it cannot penetrate substances and can only be used to sterilize surfaces.

The most common form of non-ionizing radiation is ultraviolet light, which is used in a variety of ways throughout the industry.

2-Chemical methods

Chemical sterilization is typically used for devices that would be sensitive to the high heat used in steam sterilization and for devices that can be damaged by irradiation.

Chemical sterilizers often operate using low temperature, highly reactive gases that come into direct contact with the test article (often through a semi-porous membrane or package).

The chemicals used for sterilization in this type of method are: ethylene oxide, ozone, bleach, glutaraldehyde and formaldehyde, phthalaldehyde, hydrogen peroxide, peracetic acid, silver.

One of the main concerns when performing this type of sterilization are: the possibility that the sterilant reacts with the polymeric material being sterilized; the toxic effect of residual chemicals left in the product; and operator safety associated with exposure to a sterilant.

3-Filtration method

Filtration is a method of sterilizing oil solutions or emulsions. This method works by passing the solution through a filter with a pore diameter of about 0.2mm, which is too small for microbes to pass through.

So the microorganisms are not destroyed but are retained. The filters can be filtered glass funnels made of heat fused glass particles or more commonly today, membrane filters made of cellulose esters.

The most used filters are the following:

• Core pore: polycarbonate filters that work as sieves, preventing the passage of any particle larger than the pore size.
• Depth filters: made of fibrous material that retain microorganisms by absorption and retention.
• Filtering membrane filters: the retention of microorganisms is carried out by electrostatic effects.

References

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