Terms in Sterilization

Terms in Sterilization 

Terms in Sterilization

Sterilization:

Sterilization is the process by which all viable microorganisms including spores are killed or eliminated.

There are mainly three types of sterilization procedures:

1. Physical - Heat and Radiation

2. Chemical

3. Filtration

Disinfection:

Disinfection is the destruction of vegetative pathogens but not the endospores or viruses from a surface of inanimate or inorganic objects.

Disinfectant:

Disinfectant is mainly a chemical agent used to kill microbes or reduce growth of microorganisms from any inorganic objects.

Example: Ethylene oxide, alcohols, formaldehydes.

Antisepsis:

It is the prevention of growth of microorganisms on living tissues by inhibiting their growth and metabolic activity.

Antiseptic:

Antiseptics kill or prevent microbes on living tissue.

Example: iodine, boric acid, hydrogen peroxide.

Aseptic techniques:

These are the precautionary measures taken to prevent contamination with microbes.

Radiation:

Radiation is the energy transmitted through space in a variety of forms.

There are two types of radiation -

Ionizing radiation- gamma ray, X-ray

and Non-Ionizing radiation - UV radiation.

Filtration:

Filtration is the way of passing a liquid suspension or gas through a screen like material with small pores (0.22 to 0.45 micrometer) to retain microorganisms.

Filtration is used to sterilize heat sensitive materials such as antibiotics, vaccines,  culture media, heat labile drugs and solutions for intravenous use and to prepare antisera.

Pasteurization:

It is a method of lowering microbial numbers and reduction of pathogens by heating.

Pasteurization involves 72℃ for 15 seconds, which is HTST (high temperature short time) and at 140℃ for 2 seconds, which is UHT (ultra high temperature).

Bactericidal agent:

Bactericidal agent kills bacteria and it is most effective.

They kill the

Example.  Cephalosporins

Bacteriostatic agent:

They only inhibit microbial growth but don't kill microbes.

They are less effective.

Example. Chloramphenicol.

Lyophilization:

It is a method in which low temperature decreases chemical reactions and other changes in proteins.

It is a very effective method and used for drug preservation.

Tyndallization:

Tyndallization is introduced by John Tyndall.

It is the process of fractional sterilization with free - flowing steam at 100℃ with a incubation period of 3 days.

Tyndallization is used for sterilize media, chemical solutions and biological materials.

D-value (Decimal reduction time):

D-value is the time in minutes at a fixed temperature or the radiation doses needed to kill 90% of a population of bacteria.

Z-value:

It is the increase in temperature needed to reduce the D-value of an organism by 90%.

F-value:

It represents heat treatment at any temperature as equal to that of a certain number of minutes at 121℃.

Thermal Death time (TDT):

The minimal length of time required to kill all bacteria in a liquid suspension at a fixed temperature.

Thermal Death point (TDP):

It is the lowest temperature at which all the microbes in a liquid suspension will be killed within ten minutes.

The Daily Youth- tdy24.com Presents

"Terms in Sterilization"

Written By

Sadia Akhtar

Student of Department of Microbiology

Jagannath University.

Email- sadiabd810@yahoo.com