Introduction
Microbes can cause ample diseases in humans and animals can also affect their health by spoiling the food. Therefore, it is beneficial to kill or inhibit their growth to minimize their harmful effects. A process that makes a medical device, instrument, or environment free from harmful microorganism (either by killing or inhibiting its growth)is referred to as decontamination. Decontamination can be achieved by processes like disinfection, sterilization or antisepsis. The process of killing or inhibiting the growth of microorganisms is called Disinfection and Sterilization. However, the way the two processes are conducted is quite different.
What is Sterilization?
A physical process that is followed to completely destroy all the forms of microorganisms present on any surface is called Sterilization. This process is followed mainly to preserve the substance for a longer time without decay. It is usually done by physical agents such as heat, radiation, filtration, etc.
What is Disinfection?
A process used to eliminate or inhibit the growth of bacteria and other pathogens causing infectious diseases in both humans and animals is called Disinfection. The chemicals used for this process are mainly chlorine, iodine, alcohol etc.
Methods Used in Disinfection and Sterilization
Some of the methods used in disinfection and sterilization are -
Antisepsis - It is a process in which microorganisms are destroyed in living tissue which limits the effects of infection.
Antiseptic - It is a chemical agent that is applied to living tissue to kill microbes.
Autoclave - It is a high pressure device used to allow the application of moist heat above the normal-atmosphere boiling point of water.
Biocide - They are the chemicals or substances that help to kill biological organisms.
Disinfectant - It is a germicide that kills virtually all recognized pathogenic microorganisms .
Decontamination - It is a method by which organisms are killed with no quantitative implication, generally by using the procedures for making items safe before disposal.
Factors affecting efficacy of Disinfection and Sterilization
The activities that are performed by the germicides against the microorganisms depends on a number of factors. Awareness of these factors will help us to beware of the germs. The factors affecting the efficacy of disinfection and sterilization are -
Number and location of microorganisms
Innate resistance of microorganisms
Concentration and potency of disinfectants
Physical and chemical factors
Organic and inorganic matters
Duration of exposure
Similarities Between Disinfection and Sterilization
Some common factors between Disinfection and sterilization are -
Both are used to decontaminate objects.
Both processes kill harmful microbes.
They destroy bacteria, protozoa, viruses and bacteria.
Differences between Disinfection and Sterilization
Conclusion
The main takeaway here is that the aim of disinfection and sterilization are different. The main purpose of a disinfectant is to kill or inactivate the harmful microorganisms. Sterilization, on the other hand, aims at killing all the microbes.
FAQs on Difference Between Disinfection and Sterilization
1. What is the main difference between disinfection and sterilization?
The primary difference lies in their objective. Sterilization is an absolute process that aims to completely eliminate or destroy all forms of microbial life, including highly resistant bacterial spores, from an object or surface. Disinfection, on the other hand, is a relative process that eliminates most harmful microorganisms (pathogens) but does not necessarily kill all microbial forms, especially spores.
2. What are some common real-world examples of disinfection and sterilization?
These processes are used daily in various settings:
- Examples of Sterilization: Autoclaving surgical instruments in hospitals to make them completely free of microbes, heat treatment of canned foods to ensure long shelf life, and using radiation to sterilize medical equipment like syringes.
- Examples of Disinfection: Using bleach-based cleaners on kitchen counters and bathroom surfaces, treating municipal drinking water with chlorine, and wiping down gym equipment with disinfectant wipes.
3. How do disinfectants, antiseptics, and sanitizers differ?
While related, these terms are not interchangeable. A disinfectant is a chemical agent used to destroy pathogens on inanimate objects or non-living surfaces. An antiseptic is a substance applied to living tissue, like skin, to prevent infection by inhibiting or killing microorganisms. A sanitizer is an agent that reduces the number of bacteria to a safe level, as judged by public health standards, but may not kill all of them.
4. Why is sterilization considered an absolute process while disinfection is not?
Sterilization is considered absolute because its endpoint is sterility—the complete absence of all viable microorganisms. An item is either sterile or it is not; there is no in-between. Disinfection is relative because its effectiveness is measured by the reduction in the number of pathogenic microbes. The level of disinfection can vary, from high-level (killing nearly all microbes except large numbers of spores) to low-level, depending on the chemical used and the context.
5. What are the main methods used to achieve sterilization?
As per the CBSE Biology syllabus for the 2025-26 session, sterilization can be achieved through various physical and chemical methods, including:
- Heat Sterilization: Using moist heat (autoclave) or dry heat (hot air oven).
- Chemical Sterilization: Using gases like ethylene oxide or liquids like glutaraldehyde.
- Radiation Sterilization: Using ionizing radiation (gamma rays) or non-ionizing radiation (UV light).
- Filtration: Physically removing microbes from liquids or air by passing them through a filter with microscopic pores.
6. What key factors can affect the effectiveness of both disinfection and sterilization?
Several factors determine how well a disinfectant or sterilization process works. These include the number of microorganisms present, the innate resistance of the microbes (e.g., spores are harder to kill), the concentration of the chemical agent, the duration of exposure, and the presence of organic matter like blood or soil, which can shield microbes and inactivate the chemical agent.
7. From a microbiological perspective, which types of microorganisms are targeted by disinfection versus sterilization?
Disinfection primarily targets vegetative forms of bacteria, most fungi, and lipid-enveloped viruses. However, it is generally less effective against non-enveloped viruses and highly resistant bacterial endospores. Sterilization is a more robust process designed to destroy all forms of microbial life, including the most resilient bacterial endospores, which are often used as biological indicators to validate the effectiveness of the sterilization process.
8. What is the conceptual difference between 'sterility' and the process of 'sterilization'?
This is a key distinction in microbiology. Sterility is a state or condition of being completely free from all living microorganisms. It is an absolute term. Sterilization, on the other hand, refers to any physical or chemical process that is used to achieve the state of sterility. In short, sterilization is the method, and sterility is the outcome.
