What is Sterilization?

Sterilization is a process which is used to kill or deactivate all form of microorganisms like bacteria, fungi, spores, unicellular eukaryotic organisms i.e. Plasmodium, biological agents like prions and many more. 

This process can be achieved in various ways like including heat, chemicals, irradiation, high pressure, and filtration. But this process is different from other processes like disinfection, sanitization, and pasteurization. As in those processes, we reduce microorganisms, not eliminate them. After performing the sterilization process the object is being called sterile or aseptic. 

It can also be defined as complete destruction of all microorganisms including the most resistant bacteria and spores. All microorganisms have different capacities to survive in different temperatures,  but most microorganisms die at temperatures above 800C. Whereas in the case of prions, the time required for sterilization is much higher than other microorganisms. 

How Are Microorganisms Being Killed in the Sterilization Process?

There are various methods by which microorganisms are being killed. Some of the important ones are listed below:

A. By denaturation of protein

B. By oxidation method

C. By filtration method

D. Interruption of DNA synthesis

E. Interference with protein synthesis

F. Disruption of the cell membrane

Classification of Sterilization Processes

Sterilization are classified into two types:

  1. Physical Sterilization: 

In this sterilization process we use physical methods to kill microorganisms. Methods which are used here are heat, radiation, filtration. 

  1. Chemical Sterilization

In this process, we use chemical agents to kill microorganisms. Some of the agents are alcohols, aldehydes, phenolics, oxidising agents, quaternary ammonium compounds, ethylene oxide gas, etc. 

Factors that Affect the Rate of Sterilization

Some of the common factors that influence the rate of sterilization are:

  1. Contact time

  2. Physico-chemical environment like pH

  3. Presence of organic material

  4. Temperature

  5. Types of microorganism

  6. Number of microorganism

  7. Material composition

Uses of Sterilization Process

  1. Food: During the preparation of different food items, the sterilization method is being used to kill all kinds of microorganisms present in the food item. This method is used to make food items free from all kinds of bacterias and microorganisms. As unhealthy food can cause various diseases. 

  2. In Medicine and Surgery: Before surgery, surgical instruments are being sterilized to kill all kinds of bacteria and microorganism for infection free surgery. Instruments that are sterilised are scalpels, hypodermic needles, and artificial pacemakers. Sterilization process is also mandatory in pharmaceutical companies. 

  3. Spacecraft: To protect the solar system from contamination, the sterilization process is necessary. 

Methods used in spacecraft are chemical sterilization, oxidization, ultraviolet, and irradiation.

Features of Ideal Sterilization Process

Some of the common or must be features of the ideal sterilization process are:

  1. They should be highly efficacious. 

  2. They should do the processing at a fast rate. 

  3. They should have good penetrability.

  4. They should be non-toxic in nature. 

  5. Effective despite the presence of organic material. 

  6. They should be easily monitored. 

Similarities between Sterilization and Disinfection

Things which are common in the sterilization and disinfection process:

  1. Both are these method are used to decontaminate objects and surfaces

  2. Both these processes have the ability to kill (most) harmful microbes.

FAQs (Frequently Asked Questions)

1. Can sterilization methods kill viruses?

Yes, sterilization methods have the ability to kill all viruses. These methods can also kill life forms, even transmissible agents such as bacteria, viruses, spore forms and fungi. Because of this reason, sterilised objects which we use are fully safe. Methods which we use during the sterilization process include heating, hydrogen peroxide gas, radiation, ethylene oxide gas etc.

2. Name a few food products which are being sterilized using radiation?

Some of the common food products which are being sterilised using radiations are:

Beef and Pork.

Crustaceans (e.g., lobster, shrimp, and crab)

Fresh Fruits and Vegetables.

Lettuce and Spinach.


Seeds for Sprouting

3. Define the term sterilization?

It is a kind of process which is being used to kill all types of microorganisms including its spores. We use this process to maintain a sterile environment around us. The sterilization process is mainly done by giving heat, irradiation, filtration, high pressure etc.