Microbiology: Sterilization Methods Quiz

Podcast

Play an AI-generated podcast conversation about this lesson

Questions and Answers

What is the purpose of pasteurization in milk processing?

To sterilize the milk completely

To kill pathogens without sterilizing (correct)

To increase the shelf life of milk indefinitely

To eliminate all bacteria from milk

At what temperature and duration does the Holder method of pasteurization typically occur?

72°C for 15-20 seconds

56°C for 1 hour

63°C for 30 minutes (correct)

100°C for 20 minutes

Which of the following is true about boiling as a method of sterilization?

Boiling kills all microorganisms immediately

Endospores are destroyed within 10 minutes of boiling

Boiling sterilizes liquid mediums effectively

Hepatitis virus can survive boiling for up to 30 minutes (correct)

What is the primary function of an autoclave?

To utilize steam under pressure for sterilization (D) Signup and view all the answers

Which of the following statements about the hot water bath is accurate?

It inactivates bacteria at 60°C for one hour (B) Signup and view all the answers

What is the primary action of hydrogen peroxide as an oxidizing agent?

It attacks sulfhydryl groups, inhibiting enzymatic activity. (C) Signup and view all the answers

Which of the following is NOT a use for ethylene oxide?

Used as an antibiotic treatment (C) Signup and view all the answers

What is the mechanism by which metallic salts act as disinfectants?

By coagulating proteins. (D) Signup and view all the answers

Which type of filtration is specifically suitable for heat-labile liquids?

Membrane filters (A) Signup and view all the answers

Non-ionizing radiation can be considered similar to which other method of sterilization?

Hot air sterilization (A) Signup and view all the answers

What is the primary mechanism by which dry heat sterilization operates?

Kills by oxidation effects (D) Signup and view all the answers

Which method of sterilization requires temperatures between 50°C and 300°C?

Dry heat sterilization (C) Signup and view all the answers

Which type of radiation is considered ionizing?

X-rays (A) Signup and view all the answers

What process involves the destruction of all viable microorganisms?

Sterilization (B) Signup and view all the answers

Which of the following best describes antiseptics?

Less toxic materials used on skin surfaces (B) Signup and view all the answers

What is a key purpose of using a Bunsen flame in laboratory settings?

Destroying contaminated materials (D) Signup and view all the answers

Which method effectively removes microbes from liquids and air?

Filtration (A) Signup and view all the answers

What is the main purpose of sanitization?

To remove microbes mechanically (D) Signup and view all the answers

What is the term for an agent that inhibits bacterial growth but does not kill bacteria?

Bacteriostatic (B) Signup and view all the answers

What is the recommended holding period for dry heat sterilization at 160°C?

2 hours (A) Signup and view all the answers

Which process is specifically aimed at preventing infection during surgeries?

Asepsis (D) Signup and view all the answers

What type of chemical agent is used for disinfection on inanimate objects?

Sterilants (A) Signup and view all the answers

What best describes the term 'sepsis'?

Bacterial contamination (C) Signup and view all the answers

Which of the following is NOT a physical agent for microbial control?

Gas sterilization (C) Signup and view all the answers

What does a sporicidal agent do?

Kills endospores (C) Signup and view all the answers

Which of the following is an expected result of degermation?

Mechanical removal of microbes from the skin (C) Signup and view all the answers

What is the primary goal of sterilization?

To completely remove all microorganisms, including spores (C) Signup and view all the answers

Which physical method is commonly used for sterilization?

Autoclaving (C) Signup and view all the answers

What does disinfection specifically aim to achieve?

To kill most microorganisms but not all (B) Signup and view all the answers

Which of the following is NOT a microbial growth control mechanism?

Enhancing the reproduction rate of organisms (B) Signup and view all the answers

Which disease prevention method was significantly advanced by Lister in the mid-1800s?

Aseptic techniques for surgeries (C) Signup and view all the answers

Why is ethylene oxide gas used for sterilization?

It can be used for moisture-sensitive instruments (B) Signup and view all the answers

What was the infection rate among mothers delivering in hospitals prior to the introduction of aseptic techniques?

25% (D) Signup and view all the answers

Which of the following methods is generally used to sterilize intravenous solutions?

Filtration (C) Signup and view all the answers

What is the primary mechanism through which chemical agents function?

Disruption of the cell membrane (A) Signup and view all the answers

What concentration of alcohol is recommended for effective disinfection?

60-90% in water (B) Signup and view all the answers

Which of the following statements about formaldehyde is true?

It has both bactericidal and sporicidal properties. (C) Signup and view all the answers

What is the role of iodine in antiseptic solutions?

Has moderate effectiveness against spores (A) Signup and view all the answers

What is the consequence of an organism producing catalase with regard to hydrogen peroxide disinfection?

Decreased effectiveness of hydrogen peroxide (D) Signup and view all the answers

Which of the following is a property of glutaraldehyde?

It can treat flexible materials like rubber tubes. (A) Signup and view all the answers

What is the purpose of using phenolic derivatives in hospitals?

For their potent microbicidal properties (C) Signup and view all the answers

What does the process of sterilization at 132º for 3 minutes specifically refer to?

Flash sterilization (D) Signup and view all the answers

Study Notes

Sterilization, Disinfection, and Antisepsis

Students should be able to define sterilization, disinfection, and antisepsis.
Methods of sterilization and disinfection include physical, chemical, and mechanical removal methods.
Microorganisms cause contamination, infection, and decay.
Early civilizations used methods like salting, smoking, pickling, and sunlight exposure to preserve food.
Aseptic techniques were developed in the mid-1800s to prevent contamination of surgical wounds.
Nosocomial infections (hospital-acquired infections) were a major problem before the development of these techniques, with 10% of surgical patients and up to 25% of mothers in hospitals dying from infections.
Microbial growth control methods include altering membrane permeability, damaging proteins, and damaging nucleic acids.
Prions are the most resistant, followed by bacterial spores, mycobacteria, cysts/protozoa, vegetative cells, (Gram-negative/positive) bacteria, fungi, viruses without envelopes, and viruses with lipid envelopes.
Sterilization is the process of removing all microorganisms, including spores.
Autoclaving, a common sterilization method, involves exposing materials to steam at 121°C under 15 lb/in² pressure for 15 minutes.
Surgical instruments are sometimes sterilized by ethylene oxide gas, or intravenous solutions by filtration.

Methods of Sterilization

Methods of sterilization include physical, chemical, and mechanical agents.

Physical Agents:

Heat (dry and moist), radiation (non-ionizing and ionizing).
- Dry heat methods use ovens to kill microbes.
- Moist heat methods such as autoclaving use steam under pressure. Autoclaving occurs at 121 to 132 degrees celsius at various times.
- Radiation methods to sterilize include ionizing radiation using X-rays, gamma rays, and cosmic rays and non-ionizing radiation using ultraviolet.

Chemical Agents:

Gases (ethylene oxide, hydrogen peroxide vapor, plasma gas)
Liquids (peracetic acid, glutaraldehyde)
Sterilization by chemical agents also uses disinfectants in liquids that include, formaldehyde, glutaraldehyde, chlorine, and phenols, and in solution in alcohol.
Disinfectants kill most, but not all microbes, while antiseptics are used on living tissue.

Mechanical Removal:

Filtration (air and liquids)

Disinfection

Disinfection kills many microorganisms, but not all, including bacterial spores.
Disinfectants are used on inanimate objects and materials.
Antiseptics kill microbes on living tissue.
Disinfection methods include moist heat (boiling water, pasteurization), liquids (alcohol, chlorine, phenols, hydrogen peroxide). Different chemicals have different effects and effectiveness.

Definition of Sterilization

Sterilization is the process of freeing an object from all microorganisms, including spores.

Learning Outcomes

define sterilization, disinfection, and antisepsis.
understand methods of sterilization and disinfection
explain the role of sterilization and disinfection in disease control.

Terminology

degermation
sepsis
asepsis
bactericidal
bacteriostatic
antiseptic
sterilization
disinfection
sanitation
sporicidal

Antiseptic Agents

various disinfectants and antiseptics work differenly and are used in differing concentrations based on intended goal.

Methods of Disinfection

Different methods (Moist Heat, Liquid) have differing concentration/temperature levels.

Uses of Sterlization and Disinfection Processes

various chemicals are used for different purposes, ranging from preserving specimens to sterilizing equipment for surgery.

Principles of effective disinfection

Concentration of disinfectant
Organic matter
pH
Time

Alcohols

Ethanol/Isopropyl alcohol
effective against enveloped viruses at a high concentration
No action on spores

Aldehydes

Formaldehyde
Glutaraldehyde
highly effective disinfectants

Halogens

Iodine
Chlorine-based compounds
useful for disinfection in water and swimming pools

Phenols

Phenol-based compounds
highly effective in hospitals.

Hydrogen Peroxide

Used as an antiseptic for cleaning wounds.

Gases for Sterilization

Ethylene oxide
Used for sterilization of heat-sensitive materials like heart-lung machines, respirators, sutures, and clothing, as well as some plastics, glass, metals, and some foods/tobacco.

Metallic Salts

Salts of silver, copper, and mercury are disinfectants. They coagulate proteins, inhibit bacterial growth.

Sterilization By Filtration

Removes bacteria from heat-sensitive liquids like sera and antibiotics using filters like asbestos, candle, membrane, and sintered glass filters.

Radiation methods for sterilization

Ionizing radiation includes X-rays, gamma rays, and cosmic rays, and are used to sterilize plastic syringes and catheters, fabrics, metals and grease foils..
Non-ionizing radiation includes UV light, and is used for rapid mass sterilization of pre-packaged syringes and catheters.

Ultrasonic and Sonic Vibration

Microorganisms vary in their sensitivity.
Not effective in sterilization or disinfection.

Studying That Suits You

Use AI to generate personalized quizzes and flashcards to suit your learning preferences.

Description

Test your knowledge on various sterilization methods and pasteurization techniques in milk processing. This quiz covers key concepts like the Holder method, autoclave functions, and the role of oxidizing agents. Challenge yourself with questions about non-ionizing radiation and the mechanisms of disinfectants.