Microbial Growth Control Chapter 7

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Questions and Answers

What was a major risk for patients undergoing minor surgeries until the late 19th century?

Inadequate anesthesia

Developing fatal infections (correct)

Surgeons not being trained

Failure to sterilize instruments

What does sterilization specifically refer to in modern medical practices?

Treating instruments with alcohol

Cleaning instruments with soap and water

Removing all microbes from instruments (correct)

Using heat to reduce pathogens

Which of the following practices helps to avoid microbial contamination during surgeries?

Ignoring health standards

Using outdated surgical techniques

Keeping the surgery environment cluttered

Regular hand washing (correct)

What does pasteurization entail in the context of microbial control?

Brief heating to eliminate spoilage organisms and pathogens Signup and view all the answers

What distinguishes a disinfectant from other microbial control methods?

It destroys many, but not all microbes. Signup and view all the answers

What type of microbial control is typically required in hospitals?

Sterilization Signup and view all the answers

What type of medical instruments do not penetrate body tissues and must be free of viruses and vegetative bacteria?

Critical items Signup and view all the answers

Which of the following methods is associated with preventing infection of wounds according to Joseph Lister's practices?

Application of carbolic acid Signup and view all the answers

Which environmental condition can interfere with the action of chemicals used in sterilization?

Dirt and grease Signup and view all the answers

What is a key characteristic of semicritical instruments?

They must be free of endospores. Signup and view all the answers

Which factor does NOT influence the selection of a microbial control method?

Color of the item Signup and view all the answers

What type of sterilization method is generally inappropriate for plastics and other sensitive materials?

Dry heat Signup and view all the answers

How does the food system relate to microbial control?

It demands sanitary conditions. Signup and view all the answers

What is the main focus of microbial control in daily life?

Prevention of disease transmission Signup and view all the answers

Which of the following is considered a non-critical instrument?

Stethoscopes Signup and view all the answers

Which of the following is NOT a method of microbial control?

Fermentation Signup and view all the answers

What was one of Lister's significant contributions to surgery?

Introducing antisepsis Signup and view all the answers

Which method is used to control microbial growth in water treatment facilities?

Chemical disinfection Signup and view all the answers

Which type of microorganism is most resistant to disinfectants?

Bacterial endospores Signup and view all the answers

What does the D value represent in antimicrobial procedures?

The time required for disinfectant to kill 90% of bacteria Signup and view all the answers

What factors should be considered when selecting an antimicrobial procedure?

Type and number of microorganisms present Signup and view all the answers

Which of the following describes a characteristic of non-enveloped viruses?

Have higher resistance to disinfectants Signup and view all the answers

How does population size affect the time required for antimicrobial treatments?

More organisms increase the time needed for effective antimicrobial action Signup and view all the answers

Which of the following is a drawback of using antimicrobial procedures?

They may have side effects on non-target microorganisms Signup and view all the answers

Which microorganism is known to grow in some disinfectants due to its resistance?

Pseudomonas species Signup and view all the answers

What role does washing play in the antimicrobial process?

It reduces the number of microorganisms, thus decreasing the time for treatment Signup and view all the answers

What is the process of removing or destroying all microbes called?

Sterilization Signup and view all the answers

Which method is primarily used to control pathogenic organisms in healthcare settings?

Aseptic technique Signup and view all the answers

Which of the following is a brief heating method to reduce spoilage organisms?

Pasteurization Signup and view all the answers

What is a disinfectant primarily designed to do?

Destroy many microbes but not all Signup and view all the answers

What is the primary concern of food production facilities regarding microbial control?

Ensuring products retain quality by controlling microbes Signup and view all the answers

Which Biosafety Level indicates that a microbe is not known to cause disease?

BSL-1 Signup and view all the answers

What is a significant risk associated with traditional methods of disinfecting drinking water?

Formation of disinfection by-products (DBPs) Signup and view all the answers

What role does hand washing with soap play in disease prevention?

It mechanically removes organisms from the skin Signup and view all the answers

What is the primary purpose of preservation methods for foods?

To prevent spoilage and extend shelf life Signup and view all the answers

Which of the following statements is true regarding microbial control in laboratories?

Contamination must be prevented in both samples and environment Signup and view all the answers

Study Notes

Chapter 7: Control of Microbial Growth - 1

Microbial control is necessary in many situations, including food systems needing sanitary conditions and hospitals requiring sterilization.
Learning outcomes for this chapter include:
- Using appropriate techniques (e.g., sterilization, decontamination, sanitization, pasteurization) for microbial control.
- Comparing and contrasting methods used for microbial growth control in various settings (daily life, healthcare, microbiology labs, food production, water treatment facilities).
- Explaining how factors like the type and number of microbes, environmental conditions, risk of infection, and composition of the item influence the choice of control methods.

Microbial Control

Microbial control is essential in specific situations.
Methods range from controlling sanitary conditions in food production to sterilization methods used in hospitals.

A Glimpse of History

Joseph Lister's work revolutionized surgery, improving wound care through the application of carbolic acid to prevent infections, saving lives exceeding the mortality rates of wars.
Before Lister's contributions, surgeries were high risk for infection due to a lack of understanding of microbes' spread and role in disease.
Early surgical procedures didn't sterilize instruments or maintain clean environments.

CDC Biosafety Levels

Biosafety levels range from BSL-1 (low risk), where microbes don't typically cause disease, to BSL-4 (high risk), encompassing deadly pathogens, where no vaccines or treatments are available.
Each level of biosafety has specific criteria for handling and controlling microbes.

Approaches to Control - Food and Food Production Facilities

Perishable foods remain fresh longer when contamination is eliminated.
Heating (heat treatment) is the common method and considered reliable for fresh food.
Irradiation is approved in some cases for preservation of foods, but it can affect their appearance and taste/flavor.
Additives and chemical treatments are used to prevent food spoilage. Authorities (e.g., Abu Dhabi Food Control Authority) oversee the appropriate use.

Approaches to Control - Water Treatment Facilities

Safe drinking water relies on methods to eliminate harmful pathogens.
Chlorine is a traditional disinfectant and commonly used in water treatment.
Regularly occurring chemical byproducts (DBPs) are linked to long-term health risks when present in drinking water.
Some microbes resistant to chemical disinfectants exist.
Regulations to minimize negative DBP impacts exist for water treatment facilities.

2-Selection Criteria

Choosing suitable methods for microbial control is complicated, depending on numerous factors.

Selection Criteria - Factors

Type of microbes, number of microbes, environmental conditions, risk of infection, and composition of item are key in determining the selection of an antimicrobial procedure.

Selection of an Antimicrobial Procedure - 1. Type of Microorganism

Mycobacterium species (e.g., waxy cell walls) are resistant to many chemicals.
Pseudomonas species can grow in various disinfection conditions.
Non-enveloped viruses (lacking lipid envelopes) are highly resistant.
Bacterial endospores exhibit extreme resistance.
Protozoan cysts/oocysts exhibit resistance to disinfectants.

Selection of an Antimicrobial Procedure - 2. Number of Microorganisms

Controlling microbes depends on population size, and larger populations take longer to eliminate.
Decimal reduction time (D-value) refers to the time necessary to reduce the bacterial population by 90% using a disinfectant.

Selection of an Antimicrobial Procedure - 3. Environmental Conditions

Environmental factors (e.g., dirt, grease, body fluids) reduce the effectiveness of treatments (e.g., heat).
Organisms in biofilms (and their complex structures) exhibit increased resistance.
pH and temperature are factors affecting treatment efficacy.

Selection of an Antimicrobial Procedure - 4. Risk

Medical instruments are categorized by risk for infection:
- Critical instruments come into contact with sterile tissues (e.g., needles).
- Semi-critical instruments come into contact with mucous membranes (e.g., endoscopes).
- Non-critical instruments only contact unbroken skin (e.g., stethoscopes)

Selection of an Antimicrobial Procedure - 5. Composition

Certain items (e.g., plastics) are sensitive to heat-based, liquid disinfections.
Irradiation can be an alternative, but it's sensitive to the composition of the item and risks damaging it, such as plastics.

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Description

Explore the essential techniques for microbial control in various settings such as healthcare, food production, and microbiology labs. This chapter covers methods like sterilization, decontamination, and pasteurization, while examining factors influencing their effectiveness. Gain insights into the historical impact of microbial control, particularly through Joseph Lister's contributions.