Difference Between Sterilization and Disinfection

The main difference sterilization and disinfection is that the sterilization is the complete removal of microorganisms with their resistant structures such as spores whereas disinfection is the elimination of pathogenic microorganisms. Furthermore, sterilization is an extreme level of cleanliness while disinfection is an adequate level of cleanliness.

Sterilization and disinfection are two types of decontamination methods. They can be used accordingly based on the purpose of decontamination.

Key Areas Covered

1. What is Sterilization
     – Definition, Facts, Methods
2. What is Disinfection
     – Definition, Facts, Types
3. What are the Similarities Between Sterilization and Disinfection
     – Outline of Common Features
4. What is the Difference Between Sterilization and Disinfection
     – Comparison of Key Differences

Key Terms

Bacterial Endospores, Decontamination, Disinfection, Living organisms, Sterilization

What is Sterilization

Sterilization is the removal of all forms of life of a particular microorganism. Sterilization involves both chemical and physical methods.

• Physical methods include moist heat in autoclaves, dry-heat in ovens, ionizing and non-ionizing radiation, filtration, and plasma sterilization.
• Chemical methods include glutaraldehyde, peracetic acid, ethylene oxide, formaldehyde gas, and hydrogen peroxide vapors.
  

  Figure 1: Autoclave Machine

Sterilization is important in the food processing industry, health care, and veterinary medicine which require destruction of microorganisms and their resting structures. It destroys unicellular eukaryotes such as protozoans, fungi, bacteria, viruses, prions, and their spores.

What is Disinfection

Disinfection is a process that eliminates only pathogenic microorganisms. It only destroys viable cells. It means that the method does not destroy spores. Hence, the survived spores can germinate to cause contamination later.

Types of Disinfection

• Sporicides kill spores when used in stuffiest concentrations.
• Hospital-strength disinfectants kill viable microorganisms in the presence of 400 ppm hard water and 5% organic serum.
• Broad spectrum disinfectants apply for a variety of microorganisms.
• Narrow spectrum disinfectants apply for several types of microorganisms.
  

  Figure 2: Disinfectant Liquid

The most common method of disinfection is using chemicals. To use a chemical as a disinfectant, it should have the following qualities.

1. Ability to kill microorganisms within a given period of time
2. Broad spectrum disinfection ability
3. Longer shelf life
4. Should work within a wide range of pH
5. Non-toxic or –allergic to humans and animals
6. Should be active in the presence of organic matter

Similarities Between Sterilization and Disinfection

• Sterilization and disinfection are two methods of decontamination used based on the purpose.
• Both destroy living microorganisms such as protozoans, fungi, bacteria, and virus.

Difference Between Sterilization and Disinfection

Definition

Sterilization refers to the total destruction of all microorganisms (whether or not pathogenic) and their spores, usually through the use of drastic methods while disinfection refers to the cleaning of something with chemicals to kill bacteria and other tiny living things that cause disease.

Agents

The sterilization uses more robust methods such as high heat or chemicals while disinfection uses moderately effective methods.

Methods

Sterilization uses chemicals, heat, high pressure, filtration, and irradiation while disinfection uses detergents, hydrogen peroxide, alcohols, bleach, halogens like chlorine, phenolic disinfectants, heavy metals, heating, and pasteurization.

Degree of Cleanliness

Sterilization is a method that gives extreme cleanliness while disinfection is a method that provides adequate cleanliness.

Destroy

Further, sterilization destroys both living organisms and their resistant structures while disinfection destroys only the living organisms.

Application

Looking at the applications, the common use of sterilization is to decontaminate food, medicine, and surgical instruments while the common use of disinfection is mostly to decontaminate surfaces and air.

Conclusion

Sterilization is a decontamination method that brings extreme cleanliness through killing both viable microorganisms and their spores while disinfection is a decontamination method that brings adequate cleanliness through only killing the viable microorganisms. The main difference between sterilization and disinfection is the degree of cleanliness they bring.

Reference:

1. Timothy, et al. “What Is Sterilization? 9 Sterilization Methods in Microbiology.” Study Read, 17 June 2018, Available Here
2. “Disinfection | Guideline for Disinfection and Sterilization in Healthcare Facilities (2008).” CDC, Centers for Disease Control and Prevention, 18 Sept. 2016, Available Here

Image Courtesy:

1. “Systec H-Series Autoclaves” By SystecAutoclaves – Own work (CC BY-SA 4.0) via Commons Wikimedia
2. “Disinfection liquid” By I, David Shay (CC BY-SA 3.0) via Commons Wikimedia