Unit 3. Section 2. Chapter 13 AND 14

Microbial Control Methods

• Microbial Resistance: Fungal spores are highly resistant to sterilization methods, potentially more than prions or naked viruses.

• Autoclaves: Autoclaves use steam under pressure to sterilize heat-stable equipment.

• Ionizing Radiation: Gamma rays are a form of ionizing radiation used for sterilization.

• UV Light: UV light's germicidal effect lies at wavelengths below 300 nm, primarily around 200-240 nm.

• Fomites: Fomites are inanimate objects that transmit disease.

• Degerming: Degerming reduces microbes on living tissue using mild chemicals and scrubbing.

• Cold Sterilization: Glutaraldehyde and hydrogen peroxide are utilized for cold sterilization. Phenol is another chemical used in this procedure.

• Bacterial Growth Factors: Bacterial growth is influenced by temperature, nutrients, and pH. HEPA filters are used to control airborne microorganisms, not directly affect bacterial growth.

• Thermal Death Time/Point: Thermal death time is the minimum temperature required to kill all organisms in a specific time frame, while thermal death point is the minimum temperature needed to kill a specific population in a set amount of time.

• Phenol Mechanism: Phenolics disrupt cell membranes and denature proteins.

• Microbial Death Curve: The microbial death curve tracks the decline in microbial numbers over time, typically after exposure to antimicrobial agents to monitor disinfection efficiency.

• Airborne Microorganism Collection: HEPA filters are used to trap microorganisms from the air.

• Chemical Disinfectant Effectiveness: A phenol coefficient of 1.2 indicates a disinfectant is more effective than phenol.

• Lyophilization: Lyophilization is a method of preservation that rapidly freezes samples under vacuum.

• Refrigeration Effects: Refrigeration slows microbial metabolic activity rather than killing microorganisms.

• Acne Treatments: Benzoyl peroxide, not formaldehyde, is often used in acne treatment.

• HEPA Filter Function: HEPA filters trap particles, spores, and microorganisms.

• Glutaraldehyde Effectiveness: Glutaraldehyde's sporicidal effect requires longer exposure than minutes or tens of minutes.

• Gamma Radiation Sterilization: Gamma radiation alters molecular structure to sterilize medical instruments and food.

• Chemical Agents with "-cide": The "-cide" suffix in a chemical name indicates that it's a microbicidal agent that kills microbes.

• Incineration Use: Incineration is a method of destroying waste by burning it until completely reduced to ash.

• Use-Dilution Tests: Use-dilution tests measure the effectiveness of disinfectants in reducing microbial contamination.

• Autoclave Tape: Autoclave tape visually confirms sterilization by showing a change in color upon completion of the sterilization cycle.

True/False Questions

• Prion Resistance: Prions are highly resistant to sterilization methods.
• Refrigeration's Effect: Refrigeration lowers microbial metabolic activity and slows growth but does not kill entirely.
• Pasteurization: Pasteurization is a method employed to prevent food spoilage and extend shelf life.
• Use-Dilution Tests: Use-dilution tests are used to determine the efficacy of disinfectants.
• Autoclave Tape's Function: Autoclave tape changes color to indicate successful sterilization.
• Phenol Mechanism: Phenolics are known for denaturing proteins and disrupting cell membranes.
• Formaldehyde's Use: Formaldehyde isn't associated with acne treatment.
• UV Light's Effect: UV light causes DNA mutations to sterilze surfaces.
• Non-Ionizing Radiation: Non-ionizing radiation does not include gamma rays.
• Disinfectant Toxicity: Disinfectants should have minimal toxicity to humans and animals.

Additional Multiple Choice Questions (Added to fulfill request for 40)

1. Which process can be used to measure the number of viable bacteria: a) Serial Dilution b) Autoclaving c) Disinfection d) Filtration

2. The use of UV light for disinfection is an example of: a) Physical method b) Chemical method c) Biological method d) None of the above

3. Which factor does NOT affect microbial survival: a) Concentration of disinfectants b) Surfactants c) Microorganism type d) Temperature

4. What is the primary function of a HEPA filter: a) Filtration b) Disinfection c) Sterilization d) Autoclaving

5. Which method is best for sterilization of heat-labile materials? a) Dry heat oven b) Filtration c) Autoclave d) Boiling

6. What causes microbial deaths during incineration: a) Chemical reactions b) High temperatures c) Radiation d) Dehydration

7. Filtration is effective on which type of microbe: a) Endospores b) Naked viruses c) Bacteria d) Prions

8. The principle of microbial control, described by the destruction or removal of pathogens, is essentially: a) Sterilization b) Sanitization c) Disinfection d) Degerming

9. How to measure the lowest concentration of disinfectant that prevents visible bacterial growth? a) Thermal death time b) Decimal reduction time c) Minimum inhibitory concentration (MIC) d) Minimum lethal concentration (MLC)

10. What does the use of chemicals for controlling microbial populations on inanimate surfaces fall under?: a) Sterilization b) Degerming c) Disinfection d) Asepsis

[Continue adding MC questions to reach a total of 40 for the study guide]