Fundamentals of Microbial Growth Control and Inhibition Techniques

1. What is meant by 'we live in an ocean of microbes'? Give examples.

A. Microbes are harmful pathogens that should be avoided at all costs.

D. Microbes are only found in select environments and not everywhere.

C. Gut microbes do not play a role in digestion or synthesis of important nutrients.

B. Microbes have no impact on the environment and are therefore insignificant.

Microbes are not solely harmful pathogens and play various beneficial roles in the environment and human health, as outlined in the correct answer.

Explanation

Microbes are not solely harmful pathogens and play various beneficial roles in the environment and human health, as outlined in the correct answer.

2. Why is it important to understand mechanism of growth control?

The mechanism of growth control is only relevant for agricultural purposes.

Knowing about growth control is irrelevant as modern medicine can always treat any related issues.

Understanding growth control is not important as it doesn't have any impact on daily life.

Understanding the mechanism of growth control is crucial for various aspects of public health and safety, including preventing the spread of pathogens, controlling foodborne illnesses, ensuring proper sterilization in healthcare settings, and interpreting information on consumer products.

Explanation

Understanding the mechanism of growth control is crucial for various aspects of public health and safety, including preventing the spread of pathogens, controlling foodborne illnesses, ensuring proper sterilization in healthcare settings, and interpreting information on consumer products.

3. Define sterilization, disinfection, antisepsis, degerming, and sanitization.

1. preservation of microbes2. prevention of microbial growth3. neutralizing microbial odors

4. Define the following terms: 1. nosocomial infections 2. biocide or germicide 3. fugicide 4. virucide 5. tuberculocide 6. bacteriostasis 7. sepsismicrobial death rate.

10. a chemical that inhibits growth or kills off microorganisms

8. number of dying cells per unit of time (usually per min)

9. a treatment or agent that kills parasites

The incorrect answers provided do not accurately define the terms listed in the question. Option 8. does not match with the term 'sepsismicrobial death rate.' Option 9. is incorrect because it does not match with any of the terms listed. Option 10. is inaccurate as it does not align with the definitions provided in the question.

Explanation

The incorrect answers provided do not accurately define the terms listed in the question. Option 8. does not match with the term 'sepsismicrobial death rate.' Option 9. is incorrect because it does not match with any of the terms listed. Option 10. is inaccurate as it does not align with the definitions provided in the question.

5. How do various factors influence microbial death rate?

7. Fats and proteins enhance the effectiveness of disinfectants

1. Low population load results in faster microbial death rates

5. Exposure time to agents does not influence microbial death rates

4. pH has no impact on the effectiveness of antimicrobials

2. Organic matter in human waste and bodily fluid enhances the effect of antimicrobial agents

3. Disinfectants work better at colder temperatures

6. Gram negative organisms are more susceptible to antimicrobial agents than gram positive organisms

6. What are the mechanisms of action of antimicrobial control agents?

2. promotion of viral replication

1. inhibition of cell wall synthesis

1. damage to PM2. damage to enzymes and other structural proteins3. damage to nucleic acids

3. enhancement of microbial growth

Antimicrobial control agents work by causing damage to the cell membrane, enzymes, and nucleic acids of microorganisms, leading to their destruction or inhibition of growth.

Explanation

Antimicrobial control agents work by causing damage to the cell membrane, enzymes, and nucleic acids of microorganisms, leading to their destruction or inhibition of growth.

7. What methods fall under the category of moist heat? How does this method kill? What type of organisms are killed under boiling? Pressure cooker or autoclave?

1. steaming and microwaving 2. kills by suffocating the organisms 3. all types of organisms 4. autoclave only

1. smoking and pickling 2. kills by dehydrating the organisms 3. only fungi and protozoa 4. pressure cooker only

Moist heat methods like boiling, autoclaving, and pasteurization are commonly used to kill a wide range of organisms through protein coagulation. These methods are effective against most types of organisms, including viruses and fungi, when used correctly. While pressure cookers and autoclaves are both used for moist heat sterilization, pressure cookers are more effective at killing heat resistant organisms and bacterial endospores.

Explanation

Moist heat methods like boiling, autoclaving, and pasteurization are commonly used to kill a wide range of organisms through protein coagulation. These methods are effective against most types of organisms, including viruses and fungi, when used correctly. While pressure cookers and autoclaves are both used for moist heat sterilization, pressure cookers are more effective at killing heat resistant organisms and bacterial endospores.

8. Autoclaving: What is the relationship between pressure and temperature? How do sterilization occur? What pressure and temperature kills all organisms? What works well for autoclaving? How do you sterilize surfaces and instruments?

1. The lower the pressure, the greater the temperature.

3. Steam at a pressure of 5 pounds per square inch (psi) kills all organisms.

2. Sterilization occurs by exposure to sunlight.

Autoclaving relies on the relationship between pressure and temperature for effective sterilization. The incorrect answers provided are common misconceptions that do not accurately reflect the process of autoclaving.

Explanation

Autoclaving relies on the relationship between pressure and temperature for effective sterilization. The incorrect answers provided are common misconceptions that do not accurately reflect the process of autoclaving.

9. What are some important considerations for home canning?

3. Skipping the step of driving off cold air before sealing is okay

1. Canning in glass jars is not safe

2. Using expired ingredients won't affect the canning process

When home canning, it's crucial to follow proper instructions, including using a pressure canner, following guides like Ball canning guide, ensuring no cold air is trapped in the jar before sealing, and knowing that solid items require more heat exposure to can properly.

Explanation

When home canning, it's crucial to follow proper instructions, including using a pressure canner, following guides like Ball canning guide, ensuring no cold air is trapped in the jar before sealing, and knowing that solid items require more heat exposure to can properly.

10. Dry Heat Sterilization kills how and what are examples?

1. through dehydration 2. pasteurization and boiling

1. by oxidation2. flaming and hot-air sterilization (place in oven at 170 C for 2 hrs

1. by denaturation 2. autoclaving and irradiation

1. by carbonization 2. chemical sterilization and filtration

Dry Heat Sterilization primarily works by oxidation, which destroys microorganisms. Flaming and hot-air sterilization are common examples where high temperatures are used to achieve sterilization. The incorrect answers provide alternative methods and misconceptions about the process of dry heat sterilization.

Explanation

Dry Heat Sterilization primarily works by oxidation, which destroys microorganisms. Flaming and hot-air sterilization are common examples where high temperatures are used to achieve sterilization. The incorrect answers provide alternative methods and misconceptions about the process of dry heat sterilization.

11. Other physical methods of microbial control Filtration1. removes what?2. necessary when?3. what type/size filters are used?

1. viruses or small molecules

3. filters are 1um and 10um in size; basic air filters in homes remove bacteria from air

2. to sterilize heat-resistant media only

12. Other physical methods of microbial controlLow Temperatures 1. Name the machinery and describe its function. 2. What is the temperature range of an ordinary refrigerator and what does it do to most microbes? 3. At what temperature do freezers operate and how does it affect organisms? 4. Name one important human pathogen that can grow in refrigerators.

2. Refrigeration temperature (1-5 C) is virucidal not bacteriostatic.

3. Freezer temperatures below -10 C are bacteriocidal not bacteriostatic.

1. Industrial refrigeration temperature (20-30 C) is bactericidal not bacteriostatic.

The correct answer highlights the effects of ordinary refrigeration temperature, the temperature range of freezers, and an example of a pathogen that can grow in refrigerators.

Explanation

The correct answer highlights the effects of ordinary refrigeration temperature, the temperature range of freezers, and an example of a pathogen that can grow in refrigerators.

13. Other physical methods of microbial control include:

2. UV light exposure

1. Exposure to extreme temperatures

3. Chemical disinfection

1. high salt to preserve meathigh sugar to preserve fruits2. bacteriostatic 3. drying out4. bacteriostatic

Physical methods of microbial control include high salt and sugar for preservation, bacteriostatic function, and dessication. Exposure to extreme temperatures, UV light, and chemical disinfection are other methods, but they are not specifically mentioned in the original question.

Explanation

Physical methods of microbial control include high salt and sugar for preservation, bacteriostatic function, and dessication. Exposure to extreme temperatures, UV light, and chemical disinfection are other methods, but they are not specifically mentioned in the original question.

14. Other physical methods of microbial control radiation: ionizing radiation1. uses what type of radiation2. how does it work...include energy use in explanation3. used for?4. and may become an important method for what?

2. Long wave lengths that are greater than 1 nm and carry low energy waves

3. Used for personal hygiene products, clothing, and electronic devices

1. UV rays, infrared radiation, and microwaves

Ionizing radiation includes gamma rays, electron beams, and x-rays with short wavelengths that ionize water molecules in microorganisms. This process is used for sterilizing various items like pharmaceuticals, laboratory tools, and even food. UV rays, infrared radiation, and microwaves do not have enough energy to penetrate deeply and ionize water molecules. The mentioned incorrect items do not align with the correct principles of ionizing radiation for microbial control.

Explanation

Ionizing radiation includes gamma rays, electron beams, and x-rays with short wavelengths that ionize water molecules in microorganisms. This process is used for sterilizing various items like pharmaceuticals, laboratory tools, and even food. UV rays, infrared radiation, and microwaves do not have enough energy to penetrate deeply and ionize water molecules. The mentioned incorrect items do not align with the correct principles of ionizing radiation for microbial control.

15. Nonionizing radiation uses what type of radiation, and what is the wavelength most effective for killing microorganisms?

1. X-ray radiation; 2. 100 nm; these wavelengths are specifically absorbed by cellular DNA.

1. Infrared light; 2. 400 nm; these wavelengths are specifically absorbed by cellular DNA.

1. Visible light; 2. 600 nm; these wavelengths are specifically absorbed by cellular DNA.

Nonionizing radiation specifically refers to ultraviolet light, with a wavelength of 260 nm being the most effective for killing microorganisms as these wavelengths are absorbed by cellular DNA.

Explanation

Nonionizing radiation specifically refers to ultraviolet light, with a wavelength of 260 nm being the most effective for killing microorganisms as these wavelengths are absorbed by cellular DNA.

16. What is the germicidal effectiveness of a microwave?

Highly effective in killing germs due to the heat produced during microwaving.

Completely sterilizes food and surfaces when used for cooking.

Acts as a disinfectant by eliminating all types of bacteria and viruses in the microwave.

Microwaves are not effective for germicidal treatment as they primarily cook food through heated moisture, but do not sterilize surfaces within the appliance.

Explanation

Microwaves are not effective for germicidal treatment as they primarily cook food through heated moisture, but do not sterilize surfaces within the appliance.

17. What are some key considerations for chemical methods for microbial control?

2. Concentration is not important in using chemical methods for microbial control

3. Any type of interference does not affect the effectiveness of chemical methods

1. Chemical methods are always capable of sterilization

18. What are two methods used to test the effectiveness of chemical control methods?

The Gram-staining test and the Acid-fast staining test.

The ELISA test and the PCR test.

The streak-plate test and the pour-plate test.

The use-dilution test involves exposing a metal ring dipped in bacteria to a disinfectant, while the disk-diffusion test involves placing a disk soaked in disinfectant on a lawn of bacteria on an agar plate.

Explanation

The use-dilution test involves exposing a metal ring dipped in bacteria to a disinfectant, while the disk-diffusion test involves placing a disk soaked in disinfectant on a lawn of bacteria on an agar plate.

19. Who first used chemical disinfectants like phenol and phenolics?

Alexander Fleming with the use of phenolics in penicillin

Marie Curie with the use of phenolics in radium

Isaac Newton with the use of phenol in calculus

Joseph Lister pioneered the use of phenol in carbolic acid for disinfection purposes.

Explanation

Joseph Lister pioneered the use of phenol in carbolic acid for disinfection purposes.

20. What are bisphenols and how do they differ from phenols?

3. it is a synthetic compound not found in nature

1. its molecular structure has 1 phenolic group

2. it is a type of alcohol with a single phenol group

Bisphenols have a molecular structure with 2 phenolic groups, which distinguishes them from phenols that contain only 1 phenolic group.

Explanation

Bisphenols have a molecular structure with 2 phenolic groups, which distinguishes them from phenols that contain only 1 phenolic group.

21. Biguanides acts on?

Only bacteria

Only mycobacteria

Only viruses

Biguanides are antimicrobial agents that have a broad spectrum of action against bacteria, fungi, and some enveloped viruses, but they do not work against mycobacteria, endospores, or protozoa.

Explanation

Biguanides are antimicrobial agents that have a broad spectrum of action against bacteria, fungi, and some enveloped viruses, but they do not work against mycobacteria, endospores, or protozoa.

22. Halogens: Iodine (I2) act on?

Specific types of bacteria only

Only fungi

None of the above

Iodine has a broad spectrum of action, affecting various microorganisms.

Explanation

Iodine has a broad spectrum of action, affecting various microorganisms.

23. What is the most effective form of chlorine (Cl2)?

Chloramine (NH2Cl)

Chlorine gas (Cl2) in its pure state

Chlorine dioxide (ClO2)

The most effective form of chlorine is hypochlorous acid (HOCl), which is formed when Cl gas is combined with water. This compound is widely used for disinfection purposes and has strong oxidizing properties.

Explanation

The most effective form of chlorine is hypochlorous acid (HOCl), which is formed when Cl gas is combined with water. This compound is widely used for disinfection purposes and has strong oxidizing properties.

24. What do alcohols kill, what form are they most often used in, which is the more effective solution and why, what additional function do they have, and what is their mechanism of action?

25. What are some examples of heavy metals, their past use, current use, use of copper sulfate and zinc chloride, and mechanism of action?

Each of the incorrect answers provides a set of heavy metals that do not align with the correct examples provided. The incorrect past uses, current uses, and uses of copper sulfate and zinc chloride are also unrelated to the information provided in the correct answer. Additionally, the mechanism of action given in the correct answer is not present in any of the incorrect options.

Explanation

Each of the incorrect answers provides a set of heavy metals that do not align with the correct examples provided. The incorrect past uses, current uses, and uses of copper sulfate and zinc chloride are also unrelated to the information provided in the correct answer. Additionally, the mechanism of action given in the correct answer is not present in any of the incorrect options.

26. Surface Active agents: 1. Define 2. Provide examples 3. What are they used for? 4. What is a common ingredient found in many soaps?

3. Surface active agents are primarily used for preserving food products.

4. The common ingredient found in many soaps is alcohol.

2. Examples of surface active agents are vinegar and baking soda.

1. Surface active agents increase surface tension among molecules in liquids.

Surface active agents, such as soaps and detergents, function by decreasing surface tension to facilitate the removal of dirt and microbes. Triclosan is a commonly used ingredient in soaps for its antimicrobial properties against gram positive bacteria.

Explanation

Surface active agents, such as soaps and detergents, function by decreasing surface tension to facilitate the removal of dirt and microbes. Triclosan is a commonly used ingredient in soaps for its antimicrobial properties against gram positive bacteria.

27. Quaternary Ammonium Compounds (Quats) are active on?

Water

Skin

Air

Quaternary Ammonium Compounds are primarily used on surfaces for disinfection purposes.

Explanation

Quaternary Ammonium Compounds are primarily used on surfaces for disinfection purposes.

28. What inhibits mold growth in food?

Baking powder

Sucrose

Sorbic acid; potassium sorbate; sodium benzoate; calcium propionate

Vinegar

Mold growth in food can be inhibited by using preservatives such as sorbic acid, potassium sorbate, sodium benzoate, and calcium propionate. Sucrose, vinegar, and baking powder do not have the same mold inhibiting properties.

Explanation

Mold growth in food can be inhibited by using preservatives such as sorbic acid, potassium sorbate, sodium benzoate, and calcium propionate. Sucrose, vinegar, and baking powder do not have the same mold inhibiting properties.