Difference Between Sterilization and Disinfection

Difference Between Sterilization and Disinfection

Many people confuse sterilization and disinfection and are not sure what the difference is. Here is a quick and easy guide to spot the difference between the two.

In the following context, we will try to show the difference between sterilization and disinfection, including a brief description, types, and examples.

Sterilization and disinfection are two different types of processes used to kill or eliminate microbes in a particular environment. Although both are used in the healthcare industry, they are not the same.

After the eruption of covid, you might come across the terms Disinfection, sterilization and even sanitation on a regular basis. All these phrases refer to antimicrobial procedures aimed at eradicating pathogenic microorganisms and other infectious agents.

Disinfection is a common and simple method of decontamination that we use every day. On the other hand, sterilization is mostly related to medical, industrial and scientific fields and is not often done for domestic purposes.

Sterilization can be considered as the most advanced approach to ensure the elimination of all living forms of pathogens. On the other hand, disinfection simply lowers the number of germs to a non-threatening level rather than eliminating them completely.

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However, you should first understand the significant differences between these procedures before deciding which type of asepsis is best for your situation.

Why is disinfection or sterilization necessary?

We are surrounded by a lot of microflora. For example, one gram of feces contains about 40 million bacteria, and the human mouth carries more bacteria than the entire world population. From this it is evident that microorganisms are an inseparable and inevitable part of our lives.

The majority of microorganisms live in peace; however, some are harmful to human health. For the sake of a healthy lifestyle, this harmful pathogenic flora must be eradicated. Disinfection and sterilization are procedures used to clean air, water and surfaces to remove them.

Definition of Disinfection

An antimicrobial process that targets to reduce the amount of unwanted microbial fauna contaminating to a level that is not threatening except for bacterial and vegetative spores is known as Disinfection.

The chemicals used for disinfection are known as Disinfectants. The concentration of this disinfectant determines the effectiveness and degree of disinfection. The disinfectant to be used and its concentration are the most important considerations to make.

Incorrect choice or incorrect concentration will increase costs or reduce disinfection efficiency.

Examples of disinfectant agents:

Alcohol: Alcohol acts as a dehydrating agent that denatures cellular proteins. In the healthcare sector, alcohol generally refers to a mixture of two water-soluble chemicals-isopropyl alcohol and ethyl alcohol.

Both are underrated germicidal compounds but are powerful disinfectants. Alcohol-based sanitisers are widely used for covid disinfection today. For efficient sanitation, the alcohol concentration in the cleaner should be at least 70% (with 30% water).

Chlorine and Chlorine Compounds: Chlorine-containing chemicals such as hypochlorite are the most promising disinfectant options. They are commonly used because they are accessible in both solid (eg, calcium hypochlorite) and liquid (eg, sodium hypochlorite) forms.

The most preferred concentration of sodium hypochlorite is between 5.25%-6.15%, which is commonly known as household bleach.

The mechanism of action of this chlorine disinfectant has not been determined. Nonetheless, they remain popular due to their broad spectrum antibacterial activity, hard water resistance, fast action, and cost effectiveness.

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Phenolic Compounds: Phenol is used as a disinfectant in a variety of settings, including the home, healthcare, laboratory, and industry.

The phenol derivatives ortho-phenyl phenol and ortho-benzyl-para-chlorophenol are currently the most popular. This is due to the fact that they have improvised antimicrobial properties than their parent compounds.

Their mechanism of action varies with concentration. At higher concentrations, phenol acts as a protoplasmic toxin that penetrates and damages cell walls, which ultimately precipitates cell proteins.

On the other hand, phenols with lower concentrations and higher molecular weights lead to inactivation of essential enzymes and leakage of metabolites from the cell wall.

Hydrogen peroxide: Hydrogen peroxide is considered to be risk-free, eco-friendly and safe for a sustainable environment. This is because, once removed, it breaks down into natural elements such as water and oxygen.

H2O2 acts against a wide spectrum of microbial fauna, including viruses, bacteria, fungi, yeasts, etc. Hydrogen peroxide concentration of 0.5% showed viral and bactericidal activity in 1 minute while fungicidal activity in 5 minutes.

The mode of action is based on the formation of free radicals, which can damage important biological components such as lipids, DNA, and so on.

Iodophors: Iodophors are iodine-based compounds that contain disinfecting and antiseptic properties. Its use is limited to certain semi-critical medical equipment as it retains stains and leaves an unpleasant odor.

They have a lethal effect on microorganisms as they penetrate directly into the cell wall resulting in the disruption of proteins and nucleic acids.

There are several other disinfectants such as aldehyde derivatives, quaternary ammonia compounds, peracetic acid and so on. These all have their respective advantages and disadvantages and are used in different places according to conditions.

Definition of Sterilization

The antimicrobial technique used to remove any kind of contamination, such as bacterial, fungal, and viral cells, as well as bacterial and vegetative spores, is called sterilization.

Compared to disinfection, sterilization is a high-tech approach to decontamination and cleaning. This requires special knowledge as well as certain equipment.

This is an expensive method of decontamination but is the most effective and promising way to ensure environmental safety.

Sterilization Type

The sterilization process can be classified into five categories:

1. Heating Sterilization

Heating is one of the most ancient, simple and reliable methods of sterilization. It is highly preferred because of the following advantages:

  • Kills all forms of microbes
  • Save cost
  • Doesn’t take time
  • Non-toxic
  • Safe for the environment

Heating basically kills microorganisms by coagulating or oxidizing the protein components of cells. This process of protein inactivation is called denaturation. A substance when exposed to heat for a longer duration, cellular components shrink, and microbial cells eventually die.

2. Mechanical Sterilization: Filtration

A cost-effective, attractive and easy-to-use sterilization procedure that is mostly used to sterilize liquid materials such as water, beverages and laboratory fluids.

Filtration is an effective method for sterilizing heat-sensitive liquids. When the liquid passes through the filter, unwanted particles are retained in it. The liquid obtained at the bottom is sterilized quickly and easily.

This requires the use of several types of filters (pore size – 0.2 to 0.5 m) with various pore sizes selected based on the material to be sterilized.

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3. Radiation Sterilization

Radiation is lethal to living things because it can infiltrate cells, damage nuclear material and essential biological macromolecules. The object to be sterilized is exposed to direct radiation during the radiation therapy process. As a result, all microbiological contamination on the surface is destroyed.

Despite being a very successful procedure, it has the potential to produce unwanted mutations, DNA damage, or depolymerization in those who use it. Therefore, you need to wear special safety equipment while operating this technique.

4. Chemical Sterilization

It is preferred for items that are susceptible to heat and radiation. Chemical sterilization is generally carried out by immersing equipment, tools, and equipment in a sterile liquid.

It kills microorganisms and the spores they produce. Since these sterilants can be harmful to humans, this approach must be strictly regulated.

The biggest drawback of this procedure is that the equipment often reacts chemically with the sterilant, causing damage to its composition.

Examples of some sterilant chemicals

  • Ortho-phthalaldehyde (OPA): It has fast acting antimicrobial activity. With a soaking time of 12 hours, an OPA concentration of 0.55 percent was considered optimal. It is a reusable item that does not emit a harmful odor after use.

  • Glutaraldehyde: To destroy all types of spores and microbiological contaminants, a longer soaking time (about 22 hours) is required. This is because it has a low penetration efficiency. As a result, its application is limited to low contamination zones.

5. Gas Sterilization

This method of sterilization involves treating the object with a sterilizing chemical in the form of a gas or vapor. This method is advantageous because it does not involve exposure to heat, which eliminates the risk of unwanted damage. Due to the lack of moisture, the risk of corrosion or chemical reactions is also reduced.

Plasma gas sterilization: In an enclosed space, the vaporized H 2 O 2 gas plasma is used to disinfect equipment, tools and tools. All microbial life on the surface is destroyed as soon as the gases are released inside.

This technique is environmentally friendly and safe because it produces water and oxygen as byproducts. Although it ensures full sterilization, it is quite expensive due to the special and delicate machines used.

Difference Between Sterilization and Disinfection

  1. Disinfection is an uncomplicated method that can be used anytime, anywhere, and by anyone. Not too much technical is important for disinfection purposes. On the other hand, sterilization is a complex and time-consuming procedure that requires specialized knowledge, scientific equipment and other resources.

  2. Disinfection to reduce the number of germs to a safe level where there is no risk of infection. However, sterilization ensures complete removal of the microbiome from inside and outside the object which is necessary for surgical operations, laboratory testing and R&D experiments.

  3. Disinfection is often used in the basic cleaning of floors and surfaces in households, hospitals and industry. Whereas sterilization is a typical technique that requires certain equipment and tools to be carried out efficiently. So, it is done for limited purposes where complete decontamination is demanded.

  4. Sterilization ensures the destruction of all contaminants, but due to the technicality, it becomes expensive. On the other hand, disinfection does not require any tools or machines; it’s cheaper.

  5. Disinfection is the usual technique and therefore, there is no need to follow a special protocol for it. But during sterilization, it becomes mandatory to adhere to strict protocols; otherwise, there is a risk of failure.

  6. Disinfection is able to kill almost all microbiological creatures except vegetative spores and bacterial endospores. Sterilization is advantageous here as it kills all forms of microbes along with spores.

That is the difference between sterilization and disinfection. I hope this article helped you! Thank you for visiting and don’t forget if you find this article useful, please share it with your friends too.

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