The 3 Main Sterilization Methods

The sterilization methods they are procedures by which microbial destruction is sought in objects. This means that the aim is to obtain an object free of microorganisms, decreasing 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 is the most used in food, medicine, pharmaceutical industry and surgery.

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

Most used sterilization methods 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, and all require that the temperature, gases, humidity and pressure levels used are accurately controlled to ensure their validity and effectiveness. These types of sterilization methods can be classified as follows:

1.-Physical methods (involve heat and radiation)

The heat

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

In the first case, sterilization takes place due to the denaturation and coagulation of proteins, while in the dry heat process, the cell is dried out.

• Steam : Steam sterilization, which was invented in 1880, is mainly 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 products derived from Petroleum they are often sterilized in this way. All these types have their advantages and disadvantages, but all are equal in importance to the success of a medical facility

Radiation

It is carried out at high ambient temperature 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 is used, so it can not 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.

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

The chemical products 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 is: the possibility that the sterilant reacts with the polymeric material that is sterilized; the toxic effect of residual chemicals remaining in the product; and operator safety associated with exposure to a sterilant.

3-Method by filtration

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

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

The most used filters are the following:

• Nucleophorus: polycarbonate filters that work like sieves, avoiding the passage of any particle with a larger size than the pore.
• Depth filters: made of fibrous material that retain microorganisms by absorption and retention.
• Filters of filtering membranes: The retention of microorganisms is done by the electrostatic effects.

References

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5. Pacific Biolabs._ STERILIZATION VALIDATIONS: Chemical Sterilization. Recovered pacificbiolabs.com.