Difference Between Sterilization and Disinfection

Sterilization vs Disinfection

Sterilization and disinfection are both methods of decontamination. Disinfection is aimed at killing the microbes to a level that the infection does not get transmitted and it does not necessarily kills all the microorganisms present in the equipment being disinfected. However, sterilization is a process of decontamination wherein all the microorganisms present on the surface of the equipment is killed and the object is called as sterile. Sterilization process is also known to kill all the spores present on the object to be sterilized. In short we can say that sterilization kills all the viable microorganism whereas disinfection only reduces the number of viable microorganisms.


Sterilization is a treatment that frees the treated object of all the living organisms. It can be achieved by exposure to physical, chemical agents and in case of certain solutions, by filtration. Physical methods includes heat, radiation and filtration. Chemical methods involved in sterilization includes using liquid and gaseous chemicals. Sometimes physio-chemical method which is a combination of physical and chemical method is used. Different sterilization methods commonly used include: steam sterilization, heating, chemical sterilization, radiation sterilization and sterile filtration.


Disinfection only reduces the number of microorganisms and do not completely eliminate them. The disinfection is mostly used in the practical life. Disinfection is carried out with the use of disinfectants. Disinfectants are of two types broad spectrum which acts over large variety of microorganisms and narrow spectrum which acts on small variety of microorganisms and are easy to use, non toxic and comparatively inexpensive. The different disinfectants commonly used are alcohols, aldehyde, oxidizing agent, phenolic, biguanide polymer polyaminopropyl biguanide is a bactericidal at very low concentrations, to disinfect smooth, opaque materials high density shortwave UV light, sodium bicarbonate also has some disinfectant properties.

Comparison Sterilization vs disinfection


• Disinfection only reduces the number of microorganisms whereas sterilization is the method of complete removal of the microorganisms.

• Disinfection is commonly used in daily life and practicality whereas sterilization is used in surgical operations or in labs where sterile condition is necessary.

• The sterilization methods are well defined and need to be followed strictly to completely remove the microorganisms. Disinfection does not require a very strict protocol to be followed.

• Sterilization is absolute whereas disinfection only reduces the number of microorganism and there is no guarantee that it will not result in infection.

• A sterile object has no viable microorganism present whereas disinfected object has lesser load of the microorganism.

• Disinfection can only kill vegetative form of the microorganism it cannot kill the highly resistant spores whereas sterilization can kill even the resistant spores.


Sterilization and disinfection are the methods of making an object free from contamination. Depending on the purpose of decontamination either disinfection or sterilization can be used.