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Questions and Answers
The process of using heat to kill microorganisms in food and drink is known as ______.
The process of using heat to kill microorganisms in food and drink is known as ______.
pasteurization
There are three primary ______ of disinfectants: high-level, intermediate-level, and low-level.
There are three primary ______ of disinfectants: high-level, intermediate-level, and low-level.
levels
Physical and chemical agents used for microbial control include heat, radiation, and ______.
Physical and chemical agents used for microbial control include heat, radiation, and ______.
chemicals
Moist heat methods, such as autoclaving, are generally more ______ than dry heat methods for sterilization.
Moist heat methods, such as autoclaving, are generally more ______ than dry heat methods for sterilization.
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Disinfectants that eliminate only vegetative bacteria and some viruses are classified as ______ level disinfectants.
Disinfectants that eliminate only vegetative bacteria and some viruses are classified as ______ level disinfectants.
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The process of heating liquids to kill pathogens, usually at temperatures below 100 °C, is called ______.
The process of heating liquids to kill pathogens, usually at temperatures below 100 °C, is called ______.
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Dry heat sterilization typically occurs in an electric or gas chamber heated to temperatures between 150 °C and ______ °C.
Dry heat sterilization typically occurs in an electric or gas chamber heated to temperatures between 150 °C and ______ °C.
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Incineration is a method that heats objects over 250 °C until they become ______ or turn into ashes.
Incineration is a method that heats objects over 250 °C until they become ______ or turn into ashes.
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The ______ method of pasteurization works at 71.6 °C for 15 seconds.
The ______ method of pasteurization works at 71.6 °C for 15 seconds.
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Non-pressurized steam is used in moist heat methods such as ______ at 100 °C.
Non-pressurized steam is used in moist heat methods such as ______ at 100 °C.
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To achieve de-pyrogenation, heating glassware at ______ °C for 45 minutes is recommended.
To achieve de-pyrogenation, heating glassware at ______ °C for 45 minutes is recommended.
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Moist heat sterilization at temperatures above 100 °C is done using ______ under pressure.
Moist heat sterilization at temperatures above 100 °C is done using ______ under pressure.
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The British Pharmacopoeia states that dry heat at temperatures above 220 °C may be used for the ______ of glassware.
The British Pharmacopoeia states that dry heat at temperatures above 220 °C may be used for the ______ of glassware.
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Vegetative cells exposed to normal room air gradually become ______.
Vegetative cells exposed to normal room air gradually become ______.
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Delicate pathogens, like Streptococcus pneumoniae, can die after a few hours of ______.
Delicate pathogens, like Streptococcus pneumoniae, can die after a few hours of ______.
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The method of combining freezing and drying to preserve microorganisms is known as ______.
The method of combining freezing and drying to preserve microorganisms is known as ______.
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Radiation types used for sterilization include ______, gamma rays, and UV light.
Radiation types used for sterilization include ______, gamma rays, and UV light.
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The major target for sterilizing radiation is believed to be microbial ______.
The major target for sterilizing radiation is believed to be microbial ______.
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UV light is less efficient than electron or gamma irradiation because it causes ______ damage.
UV light is less efficient than electron or gamma irradiation because it causes ______ damage.
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The optimum wavelength for UV sterilization is around ______ nm.
The optimum wavelength for UV sterilization is around ______ nm.
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Operators in an irradiated room should wear appropriate ______ clothing.
Operators in an irradiated room should wear appropriate ______ clothing.
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UV light is unsuitable for sterilization of pharmaceutical dosage forms due to its poor ______.
UV light is unsuitable for sterilization of pharmaceutical dosage forms due to its poor ______.
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Moist heat is often used for sterilization, while dry heat uses ______ methods.
Moist heat is often used for sterilization, while dry heat uses ______ methods.
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________ is the process of heating liquids to kill pathogenic microorganisms.
________ is the process of heating liquids to kill pathogenic microorganisms.
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The stages of operation in sterilization include preparation, sterilization, and ________.
The stages of operation in sterilization include preparation, sterilization, and ________.
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Physical agents for microbial control include heat, radiation, and ________.
Physical agents for microbial control include heat, radiation, and ________.
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Moist heat can cause protein denaturation and is more effective than dry heat at ________ temperatures.
Moist heat can cause protein denaturation and is more effective than dry heat at ________ temperatures.
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The Thermal Death Time (TDT) is the time required to kill all test microbes at a specified ________.
The Thermal Death Time (TDT) is the time required to kill all test microbes at a specified ________.
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The Thermal Death Point (TDP) is defined as the lowest temperature needed to kill all microbes in ________ minutes.
The Thermal Death Point (TDP) is defined as the lowest temperature needed to kill all microbes in ________ minutes.
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In terminal sterilization, the goal is to achieve a certain level of Sterility Assurance Level (SAL) to ensure ________.
In terminal sterilization, the goal is to achieve a certain level of Sterility Assurance Level (SAL) to ensure ________.
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Aseptic processing is used to create a sterile environment for drug products without using ________ sterilization.
Aseptic processing is used to create a sterile environment for drug products without using ________ sterilization.
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The innate resistance of microorganisms can affect the ________ effectiveness of sterilization methods.
The innate resistance of microorganisms can affect the ________ effectiveness of sterilization methods.
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Physical and chemical factors such as pH and relative humidity can greatly influence the ________ process.
Physical and chemical factors such as pH and relative humidity can greatly influence the ________ process.
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The process of heating milk to kill harmful microorganisms is known as ______.
The process of heating milk to kill harmful microorganisms is known as ______.
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In the autoclaving process, the final stage consists of ______ or cooling.
In the autoclaving process, the final stage consists of ______ or cooling.
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Moist heat is more effective than ______ heat for microbial control.
Moist heat is more effective than ______ heat for microbial control.
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Tyndallization is a method of disinfection that involves exposing items to ______ °C unpressurized steam.
Tyndallization is a method of disinfection that involves exposing items to ______ °C unpressurized steam.
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The temperature in autoclaving for porous loads, such as surgical dressings, is ______ °C for 3 minutes.
The temperature in autoclaving for porous loads, such as surgical dressings, is ______ °C for 3 minutes.
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Cold treatment primarily serves to slow the growth of ______ in food and perishable materials.
Cold treatment primarily serves to slow the growth of ______ in food and perishable materials.
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Boiling water can effectively kill vegetative pathogens if items are submerged for at least ______ minutes.
Boiling water can effectively kill vegetative pathogens if items are submerged for at least ______ minutes.
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The principal benefit of cold treatment is to ______ the growth of cultures during processing.
The principal benefit of cold treatment is to ______ the growth of cultures during processing.
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The temperature/time cycle for sterilizing bottled fluids in an autoclave is ______ °C for 15 minutes.
The temperature/time cycle for sterilizing bottled fluids in an autoclave is ______ °C for 15 minutes.
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Steam under pressure is more effective in killing spores and pathogens than regular ______ methods.
Steam under pressure is more effective in killing spores and pathogens than regular ______ methods.
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Study Notes
Introduction to Microbial Control
- Control of microorganisms is crucial for preventing disease transmission, stopping spoilage, and preventing contamination.
Antimicrobial Agents
- Antimicrobial agents are traditionally divided into antibiotics and chemical biocides.
- Chemical biocides include antiseptics, disinfectants, and preservatives.
Target Sites and Modes of Action
- Antimicrobial agents primarily disrupt cell walls, membranes, or cellular proteins/nucleic acids.
- Resistance to biocides tend to occur less frequently than with antibiotics.
Factors Influencing Biocidal Activity
- Temperature: Higher temperatures generally increase biocidal activity.
- Concentration: Higher concentrations often enhance activity but have limits.
- pH: The pH of the solution affects the activity of some biocides.
- Solubility: Solubility influences the effectiveness of the biocide.
- Interaction with excipients/packaging: Biocides can bind to materials affecting their efficacy.
- Interaction with organic/inorganic material: Organic matter can hinder biocide efficacy.
- Number and location of microorganisms: Microorganism concentration and location impact biocide activity.
- Biofilms: Biofilms may hinder biocide action.
Specific Biocides: Halogens
- Chlorine and iodine are common germicidal preparations.
- Their effects are primarily in their nonionic state, not as halide.
Specific Biocides: Chlorine
- Used in large-scale water disinfection and sanitation of food equipment.
- Hypochlorites are frequently used as a disinfectant.
- Chloramines are used as an alternative to pure chlorine for water treatment.
Specific Biocides: Iodine
- Often used as an antiseptic, for wound preparation and equipment disinfection.
- Iodophors offer a slow release with low toxicity compared to elemental iodine, often used in aqueous solutions or tinctures.
Specific Biocides: Phenolic Compounds
- Phenol is an acrid, poisonous compound derived from coal tar.
- Alkylated phenols (cresols) and chlorinated phenols (triclosan, bisphenols) offer less toxicity.
- Effective against vegetative bacteria, fungi, and some viruses.
Specific Biocides: Chlorhexidine
- Chlorhexidine (Hibiclens, Hibitane) targets cell membranes, denatures proteins, and is highly effective against bacteria.
- Less effective against bacterial spores.
Specific Biocides: Alcohols
- Ethyl and isopropyl alcohols are suitable for microbial control.
- Activity increases with higher concentration (but not 100% alcohol) through disruption of microbial membranes and proteins.
Specific Biocides: Hydrogen Peroxide
- Decomposes into water and oxygen gas, producing potent hydroxyl radicals (bactericidal, virucidal, fungicidal, even sporicidal in higher concentrations).
- 3% Hydrogen peroxide is a common treatment in treating anaerobic bacterial infections.
- 35% vaporized hydrogen peroxide is a major sterilant.
Specific Biocides: Aldehydes
- Glutaraldehyde and ortho-phthalaldehyde (OPA) are strong, cross-linking protein inhibitors effective against a wide range of microbes, especially spores
- Formaldehyde: A gas that readily dissolves in water to form formalin. Useful for intermediate-high-level disinfection, but is less clinically useful due to toxicity and skin irritation.
Specific Biocides: Gases-Ethylene Oxide and Chlorine Dioxide
- Ethylene oxide and propylene oxide are colorless gases that are potent alkylating agents, used in chemical sterilization—sporicidal.
- Chlorine dioxide is an alkylating agent used to treat water, wastewater, and medical waste.
Specific Biocides: Detergents and Soaps
- Detergents and soaps are surfactants that disrupt cell membranes, primarily on sensitive microbes.
- Many anionic detergents have limited microbicidal power. Cationic detergents, including quaternary ammonium compounds (quats), are substantially more effective.
Specific Biocides: Heavy Metals
- Higher molecular weight metals (mercury, silver, gold) can be very toxic, even in minute quantities, and inhibit microbial growth.
- These are often referred to as heavy metals because of their relatively high atomic weights.
Specific Biocides: Dyes
- Dyes can be antimicrobial agents.
- They stain and have limited activity, used primarily as antiseptics and in wound treatment.
Specific Biocides: Acids and Alkalis
- Highly acidic or alkaline conditions can destroy or inhibit microbes.
- Organic acids are often used as food preservatives because they prevent spore germination and microbial growth. (e.g., acetic, propionic, lactic, benzoic, and sorbic acids).
Typical Routes of Antimicrobial Administration
- Details on typical administration routes, including topical, oral, and parenteral, for specific antimicrobials.
Antimicrobial Resistance Mechanisms
- Drug inactivation
- Decreased permeability
- Drug pumps activation
- Change in drug binding site
- Use of alternate metabolic pathway.
Factors Affecting Effectiveness of Antimicrobial Agents
- Population size: Larger populations require longer exposure times.
- Population composition: Organisms vary in susceptibility to antimicrobial agents. Spores and other dormant forms are typically more resistant than vegetative cells.
Types of Disinfectants: High-Level, Intermediate-Level, Low-Level
- Specific descriptions of the different levels of disinfectants—high-level disinfectants, intermediate-level disinfectants, and low-level disinfectants with details about their applications and targets
Selecting a Microbicidal Chemical
- Rapid action, low concentrations are needed.
- Solubility in water or alcohol.
- Broad-spectrum action, without toxicity.
- Penetration of surfaces for sustained antimicrobial activity, and resistance to deactivation by organic matter.
- Non-corrosive and non-staining.
Methods for Testing Disinfectant Efficacy
- Suspension tests: Include the phenol coefficient test and Rideal-Walker test, chick Martin test.
- Capacity tests: Evaluate disinfectant's ability to sustain activity in the face of an increasing load of microbes. A specific method is the Kelsey-Sykes test.
- Surface tests: Assess the effectiveness of disinfectant against dried organisms on surfaces. Methods include disk diffusion test and various dilution tests.
Antiseptic, Disinficants, and Preservative Categories Breakdown
- Lists of common and categorized antimicrobial chemical agents
Halogen Compounds: Further Details
- Descriptions of the specific modes of action and uses of chlorine and iodine in germicidal preparations.
Other Physical Methods of Microbial Control
- Sterilization using heat (moist heat and dry heat), radiation, and filtration
Definitions of Sterility, Methods for Determining Sterility, and Microbial Testing and Procedures
- Define sterility and the different ways to test for sterility.
Testing Efficacy of Disinfectants
- Testing methods that determine a chemical's antimicrobial activity—in particular, the types of organisms affected.
- Include information about the regulatory bodies involved in approval testing, including FDA, EPA, and AOAC.
Factors Affecting Sterilization
- Factors affecting the outcome of sterilization—such as the number and location of microorganisms, the microbes' innate resistance, physical factors (e.g., temperature, pH, relative humidity), and exposure duration.
Introduction to Fermentation
- Definition of fermentation, including that it is the transformation of sugars.
- Its significance in biotechnology and human history
Typical Products of Microbial Synthesis
- Include large molecules such as enzymes, and proteins, from both natural and bioengineered forms
Microbial Growth in Relation to Synthesis of Metabolites
- Explains how different phases of microbial growth relate to the production of different types of metabolites (primary and secondary).
Types of Fermentation
- Categorizes the types of fermentation, such as aerobic versus anaerobic or batch versus continuous
Commercial Production of Antibiotics
- Describes the history of penicillin discovery and its production, including strain selection and improvement of fermentation processes.
Overview/Introduction to Biologicals
- Details concerning biological therapeutic classes, such as monoclonal antibodies, growth factors, cytokines and vaccines
Vaccine Production/Processing Methods/Quality Control
- Include information about the stages of vaccine development, testing, and production process, from selecting the strain to final product control.
Antimicrobial Chemotherapy (Introduction and General Approach)
- Defining chemotherapy: use of chemical agents to treat infectious diseases, including categories for prophylaxis, empiric use, and definitive therapy.
- Understanding some rules of optimal use of antibiotics.
Antimicrobial Resistance Mechanisms and Effects
- Provides details about the mechanisms that cause antimicrobial resistance.
Determination of Microbial Sensitivities to Antimicrobial Agents
- Methods for determining microbial sensitivities to specific antimicrobial agents, including the disk diffusion tests (Kirby-Bauer) and dilution tests to establish MIC (minimal inhibitory concentration) and MBC (minimal bactericidal concentration)
- Describing the importance of the Clinical and Laboratory Standards Institute (CLSI) guidelines.
Summary of F-Value Information
- Provides summary information to assist in preparing for a deeper dive into F-value, the temperature/time combination for sterilization using, for example, an autoclave unit.
Specific Microbial Agents (Grouping by Target)
- Organism groups based on the target of antimicrobial treatment that is blocked, such as cell wall inhibitors, DNA/RNA inhibitors, or protein synthesis inhibitors.
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Description
Test your knowledge on various methods of microbial control, including sterilization and disinfection techniques. This quiz covers the key concepts of heat, radiation, and chemical agents used to eliminate microorganisms in food and drink. Perfect for students of microbiology and food safety!
