a brief into different method of sterilization

1. Different Method of Sterilization
Prepared By
Abhijeet
B. Pharm{2019-2023}

2. CONTENTS
 Introduction
 Methods of Sterilization

3. INTRODUCTION
 Sterilization is a broad term that refers to any process that removes or kills all
forms of microorganisms. This include bacteria, fungi, viruses and protozoans.

4. Method of Sterilization
 Various Methods of Sterilization are as following:
1. Physical Method
a. Dry heat sterilization
b. Moist heat sterilization
c. Sterilization by Radiation
d. Filtration
2. Chemical Method
a. Gaseous Method
b. by using disinfectants

5. PHYSICAL METHODS:
 A. Dry heat sterilization
Heat is the most reliable and rapid method of sterilization.
Dry heat kills microorganism by causing protein denaturation and destructive
oxidation of essential cell.

6. Various methods of sterilization by dry
heat include:
 1. Sunlight: Direct sunlight has sterilizing effect due to presence of UV rays and
heating effect of infra red rays.
2. Red Heat: Inoculating wires, loop, spatulas and forceps are sterilized by holding
them on a flame of Bunsen burner.
3. Flaming: Glass slides, cover slip, needles are sterilized by Passing them over the
flame of Bunsen burner without allowing it to become red hot.
4. Incineration: Efficient method for destroying infective material like pathological
material or contaminated cloth by reducing them to ashes by burning.

7. Contd. Dry heat
 5. Hot air oven: It is widely used method of sterilization by dry heat.
It is electrically heated and thermostatically controlled by exposing material at 160c
for 1 hour.

8. Moist Heat Sterilization
 B. Moist heat sterilization
Killing of microorganism with hot water or steam.
Divided into three forms in terms of temperature:
1. Temperature below 100c:
Pasteurization: It is a process in which milk is heated and cooled immediately
It is also used for ice cream, yogurt and fruit juices.
Two methods are generally used:

9. Contd. Moist Heat Sterilization
a. Holder method: 62.8C for 30 minute.
b. Flash method: 72C for 20 seconds

10. Contd. Moist Heat Sterilization
 2. Temperature at 100C :
Tyndallization: Steam at 100C for 20 minutes on three successive days. Used for
egg, serum and sugar containing media.
Boiling: Boiling for 10-30 minutes kills mostly the vegetative form of bacteria.
3. Temperature above 100C:
Autoclave: It is a modified pressure cooker in which sterilization is achieved by
saturated steam under high pressure at 121C for 15 minutes.

11. Sterilization by Radiation
 C. Sterilization by Radiation
Two types of radiation: Ionizing and Non-ionizing radiation.
1. Non-ionising radiation(Hot sterilization)
Infrared- Used for rapid mass sterilization of pre-packed items such as syringe.
UV- Used for disinfecting enclosed area such as hospitals and labs.

12. Contd. Sterilization by Radiation
2. Ionising sterilization(Cold sterilization)
Done by using Gamma rays and X rays.
Used for sterilising plastics, syringes, swabs, fabric and metal foils.

13. Filtration Method
 D. Filtration
This method is used for the sterilization of liquid substance or fluid such as sera
and solutions of heat labile substance.
Types of filter:
1. Candle filter
2. Asbestos filter
3. Sintered glass filter
4. Membrane filter

14. Contd. Filtration Method
 1. Candle filter
It is widely used for the purification of water for industrial and drinking purposes.
2. Asbestos filter
It is disposable and single disc made up of asbestos(magnesium trisilicate)
Pore size of filter ranges from 0.01 to 5micron.

15. Contd. Filtration Method
3. Sintered glass filter
It has low absorptive properties
They are brittle and expensive .
4. Membrane filter
Made up of cellulose esters and other polymers,
Usually used for the purification of water and sterile testing for parenteral use.

16. CHEMICAL METHODS:
 1. Gaseous Method
The most common gas used in gaseous sterilization is ethylene oxide.
It is a colourless liquid with BP 10.8.
Ethylene oxide is widely used gaseous sterilizing agent in medical science.
ADVANTAGES-
It is powerful sterilizing agent for surgical instruments.
DISADVANTAGES-
Low sterilization process.

17.  2. By using disinfectants
Phenol, alcohol, dyes, aldehydes, etc. can be used as a disinfectant or antimicrobial
agent.