Sterilization Techniques PDF

 ACTIVITY 1 Instructions. Analyze the given picture below Guide Questions 1. Describe the picture below. 2. What precautionary measures...

 ACTIVITY 1 Instructions. Analyze the given picture below Guide Questions 1. Describe the picture below. 2. What precautionary measures should be considered when using a bottle for a baby? 3. Why is that technique important for the baby’s health? "In what ways do you think this process contributes to the effectiveness of laboratory operations? Please explain."  Think about this!! Why do we need to sterilize laboratory tools and materials?  Lesson Objectives 1. dentify and explain the purpose of different sterilization techniques used in laboratory settings. 2. Compare the advantages, disadvantages, and applications of autoclaving, filtration, radiation, and chemical sterilization. 3. Perform and demonstrate proper sterilization techniques based on a specific laboratory scenario. METHODS OF STERLIZATION  DEFINITION Sterilization is the removal of all forms of microorganisms from the surface of an object. GENERAL OBJECTIVE OF STERLIZATION Sterilization is done to avoid the growth of microorganisms which may grow on the surface of an object if left without killing the germs It is, however, different from disinfection or sanitization where only reduction of the microorganisms takes place, rather than total elimination. After sterilization, an object becomes sterile or aseptic.  TYPES OF STERLIZATION A. Physical Sterilization 1) Heat Sterilization Moist Heat Sterilization (Autoclaving) Dry Heat Sterilization (incinerators, hot air oven, flaming techniques) 2. Filtration 3. Radiation Non-Ionizing Radiation Ionizing Radiation 4. Sound Wave Vibration 5. Fractional Sterilization  TYPES OF STERLIZATION B. Chemical Methods of Sterilization 1. Gaseous Sterilization 2. Liquid Sterilization 3. Cold Sterilization PHYSICAL STERIZATION  MOIST HEAT STERILIZATION It is one of the best methods of sterilization. Moist heat sterilization is done with the help of an instrument called an autoclave. An autoclave works on the principle of producing steam under pressure. Thus moist heat sterilization is also known as steam sterilization. The water is boiled in an autoclave at 121-134℃ at a pressure of 15psi. This leads to coagulation of proteins in the microorganism, and they are effectively killed.  STEPS IN USING AUTOCLAVE Post Sterilization Unloading Care the Cooling Autoclave and Starting the Venting Cycle Setting Parameters Loading the Autoclave Preparation HOW TO USE AN AUTOCLAVE  DRY HEAT STERILIZATION This method is used on objects that are sensitive to moisture. Moisture-free heat or dry heat is applied on the surface or objects such that there is denaturation and lysis of proteins which leads to oxidative damage, and ultimately the microbial cell dies out or may even burn.  2. FILTRATION This is a mechanical method of sterilization in microbiology. This method uses membranous filters with small pores to filter out the liquid so that all the bigger particles and microbes cannot pass through. Microfiltration Syringe Filter The three steps of filtration are sieving, adsorption and trapping.  Radiation The process of exposing surfaces or objects to different kinds of radiation for sterilization  Radiation Sterilization Non-Ionization Radiation Ionizing Radiation Ultraviolet radiation is Upon exposure to ionizing exposed to the object, which radiations such as gamma is absorbed by nucleic acids rays and X-rays, reactive of the microorganisms. oxygen species such as This leads to the formation hydrogen peroxide and of pyrimidine dimers in the superoxide ions are formed DNA strand, which causes that oxidise the cellular the replicative error, and components of the microbe, eventually, the microbe dies. and they die.  Sound Waves Vibration Sonix sound waves ranging from 20-40 kHz in frequency are applied across the fluid to be sterilized. These ultrasonic waves produce an alternation of compressive and tensile forces forming cavities in the solution. These cavities suddenly collapse, which creates submicroscopic voids and removes microorganisms from the container.  FRACTIONAL STERILIZATION Fractional sterilization or tyndallization is a method used for media containing gelatin or sugar. Typically, exposure to 100°C for 20 minutes on 3 successive days is required. The principle is that the first exposure kills all spores and vegetative bacteria. If they germinate, they will be killed in the subsequent exposures. However, this method may fail to kill spores of certain thermophiles and anaerobes.  Advantages of Physical Sterilization Sterilization Advantages Disadvantages Technique Efficient and reliable for most materials; kills all Not suitable for heat-sensitive Heat Sterilization forms of microbes. materials; may cause degradation. Limited to removing larger Ideal for heat-sensitive liquids and gases; Filtration microorganisms; ineffective for maintains sample integrity. small viruses. Expensive; requires safety Effective for disposable medical tools and Radiation precautions and specialized surfaces; no heat required. equipment. Sound Wave Non-invasive; useful for cleaning delicate Limited sterilization capabilities; Vibration instruments. often used as a cleaning aid. Fractional Suitable for certain heat-sensitive materials; Requires multiple cycles; less effective Sterilization simple equipment needed. than other methods. Chemical Methods of Sterilization  Definition Chemical methods of sterilization are used in microbiology for biological specimens and plastic equipment. In this method, several chemicals work as bactericidal agents. They can be of two types: gaseous or liquid.  Gaseous sterilization is the method where the object is exposed to gas in a closed, heated and pressurized chamber. The gaseous chemical agents used for sterilization include ethylene oxide, formaldehyde, nitrogen dioxide and ozone.  Liquid Sterilization Liquid sterilization is the process of immersing the object in a liquid such that it kills all the viable microorganisms and their spores. This method is less effective than gaseous sterilization and is used to remove low levels of contamination. Common liquid chemical agents that are used for sterilization include hydrogen peroxide, glutaraldehyde and hypochlorite solution. Advantages and Disadvantages of Gas and Liquid Sterilization Sterilization Method Advantages Disadvantages Effective for heat- and Toxic gases (e.g., ethylene Gas Sterilization moisture-sensitive oxide) require special materials; penetrates well. handling and ventilation. Useful for heat-sensitive Residual chemicals may Liquid Sterilization materials and surface remain; some liquids can sterilization. damage sensitive materials. Let’s Apply  Instructions Identify and explain the appropriate sterilization techniques based on the given scenario. Put your answer in a 1/2 crosswise paper  Sterilization Scenario Explanation Technique A microbiology lab sterilizes glass petri dishes Heat Sterilization and metal inoculating loops using an autoclave. A pharmaceutical company filters heat-sensitive Filtration antibiotics to remove bacteria and particulates. A hospital uses gamma radiation to sterilize Radiation disposable syringes and surgical gloves. Sound Wave A dental clinic uses ultrasonic cleaners to clean Vibration delicate dental instruments before autoclaving. Fractional A research lab sterilizes nutrient media containing Sterilization heat-sensitive components over several days. A medical equipment manufacturer sterilizes Gas Sterilization plastic catheters using ethylene oxide gas.