Deck 9: Controlling Microbial Growth in the Environment

Question 1

Aseptic means

A) sterile.
B) free of all microbes.
C) clean.
D) sanitized.
E) free of pathogens.

Answer 1

E

Question 2

Which of the following is the most difficult to inactivate?

A) enveloped viruses
B) fungus spores
C) bacterial endospores
D) nonenveloped viruses
E) protozoan cysts

Answer 2

C

Question 3

Antimicrobial agents that damage nucleic acids also affect

A) the cell wall.
B) the cell membrane.
C) the viral envelope.
D) endospores.
E) protein synthesis.

Answer 3

E

Question 4

Which of the following is used for microbial control in fresh fruits and vegetables?

A) X rays
B) ultraviolet light
C) electron beams
D) microwaves
E) gamma rays

Question 5

Which of the following is NOT a feature associated with filtration?

A) nitrocellulose or plastic membrane filters
B) sterilization of heat-sensitive materials
C) varying thicknesses of membrane filters used
D) use of HEPA filters to filter air
E) ability of some filters to trap viruses and proteins

Question 6

Which of the following types of radiation is nonionizing and has the shortest wavelength?

A) ultraviolet light
B) infrared radiation
C) microwaves
D) X rays
E) gamma rays

Question 7

Which of the following is bacteriostatic?

A) heating in an oven at 171°C for an hour
B) freezing below 0°C
C) filtration
D) autoclaving
E) flash pasteurization

Question 8

Which of the following can be used to reduce microbes in the air of a patient's room?

A) HEPA filters
B) ethylene oxide
C) ultraviolet light
D) both HEPA filters and ultraviolet light
E) both ethylene oxide and ultraviolet light

Question 9

Which of the following is the most appropriate pairing of microbe and biosafety level?

A) E. coli, BSL-3
B) anthrax, BSL-1
C) Ebola, BSL-2
D) methicillin-resistant Staphylococcus aureus (MRSA), BSL-2
E) tuberculosis, BSL-1

Question 10

Washing dishes in the dishwasher with detergent and hot water is a ________ process.

A) antiseptic
B) disinfecting
C) sterilizing
D) sanitizing
E) degerming

Question 11

Which of the following describes flash pasteurization?

A) heating at 63°C for 30 minutes
B) heating at 72°C for 15 seconds
C) heating at 72°C for 15 minutes
D) heating at 134°C for one second
E) passing liquid through steam at 140°C

Question 12

Methods of microbial control called ________ arrest the growth of microbes.

A) microbicial
B) microbistatic
C) sanitizing
D) degerming
E) antiseptic

Question 13

Boiling water for 10 minutes is effective in ridding it of

A) actively growing bacteria.
B) enveloped viruses.
C) bacterial endospores.
D) protozoan cysts.
E) both growing bacteria and enveloped viruses.

Question 14

Ultra-high-temperature sterilization effectively

A) reduces microbes that cause spoilage.
B) removes only mesophilic microbes.
C) reduces microbes that cause disease.
D) removes all microbes that cause diseases or spoilage.
E) reduces microbes that cause disease or spoilage.

Question 15

Which of the following is an example of pasteurization?

A) A public toilet is treated with disinfectants.
B) A surgeon washes her hands before surgery.
C) Heat is used to kill potential pathogens in apple juice.
D) An autoclave is used to prepare nutrient agar.
E) A nurse prepares an injection site with an alcohol swab.

Question 16

Silvadene, a topical treatment for burns, contains 1% silver. What category of chemical control agent is in Silvadene?

A) halogens
B) heavy metals
C) oxidizing agents
D) aldehydes
E) surfactants

Question 17

You notice a sign in a public restroom that states "Sanitized for your safety." This means

A) sterilizing chemicals have been used in cleaning.
B) antiseptics have been used to clean the area.
C) degerming methods only have been used to clean the restroom.
D) methods of disinfection that meet minimum standards of microbial removal have been used.
E) only "organic" chemicals were used in the cleaning process to reduce microbial numbers.

Question 18

An instrument that will come into contact with only the skin of a patient should be disinfected with a(n)

A) high-level germicide.
B) low-level germicide.
C) intermediate-level germicide.
D) degerming agent only.
E) germistatic agent only.

Question 19

Which of the following statements is TRUE of disinfectants?

A) They are effective in destroying endospores.
B) They are used on living tissue.
C) They are used for sterilization.
D) They are used on inanimate surfaces.
E) They are only effective for short periods of time (seconds to minutes).

Question 20

A chemical agent that dissolves lipids can damage

A) cells.
B) bacterial endospores.
C) enveloped viruses.
D) nonenveloped and enveloped viruses.
E) cells and enveloped viruses.

Question 21

Which of the following is NOT a desirable characteristic of an ideal antimicrobial agent?

A) it is inexpensive.
B) it is stable during storage.
C) it is harmless to humans.
D) it only arrests growth of vegetative cells.
E) it acts quickly.

Question 22

Hydrogen peroxide is an effective

A) sterilizing agent.
B) disinfectant.
C) antiseptic.
D) disinfecting and sterilizing agent.
E) antiseptic and disinfectant.

Question 23

Which of the following is a sterilizing agent?

A) ozone
B) hydrogen peroxide
C) peracetic acid
D) dish soap
E) ozone and hydrogen peroxide

Question 24

Quaternary ammonium compounds ("quats") are used for

A) antisepsis.
B) disinfection.
C) sterilization.
D) quantifying antimicrobial activity.
E) both antisepsis and disinfection.

Question 25

Which of the following is used to sterilize items that should not, or cannot, be exposed to heat or water?

A) ethylene oxide
B) formaldehyde
C) hydrogen peroxide
D) calcium hypochlorite
E) triclosan

Question 26

Why are endospores used to measure the effectiveness of autoclave sterilization?

A) Endospores are easy to store in the lab until needed.
B) Endospores are very simple structures and easy to detect.
C) Endospores are very hard to kill.
D) Endospores are composed of all the molecules found in living cells.
E) Endospores of different bacteria are destroyed at different temperatures and can be used to calibrate autoclave temperatures.

Question 27

The process of filtration is a(n)

A) disinfectant method.
B) sterilizing method.
C) sanitization method.
D) antiseptic procedure.
E) ineffective method for removing microbes.

Question 28

Which of the following procedures is currently the standard test used in the United States for evaluating the efficiency of antiseptics and disinfectants?

A) use-dilution test
B) microbial death rate
C) in-use test
D) Kelsey-Sykes capacity test
E) phenol coefficient

Question 29

Disinfectants that damage membranes include

A) alcohol.
B) phenolics.
C) iodine.
D) hydrogen peroxide.
E) both alcohol and phenolics.

Question 30

The use of lysozyme during the preparation of cheeses and wines is effective in reducing the numbers of

A) fungi.
B) viruses.
C) bacteria.
D) prions.
E) all microbes.

Question 31

Alcohols are used for

A) disinfection.
B) sterilization.
C) antisepsis.
D) both sterilization and disinfection.
E) both antisepsis and disinfection.

Question 32

A chemical agent that kills pathogenic microbes in general is a(n)

A) sanitizer.
B) germicide.
C) disinfectant.
D) fungicide.
E) antiseptic.

Question 33

Seventy percent alcohol is effective against

A) enveloped viruses.
B) nonenveloped viruses.
C) bacterial endospores.
D) protozoan cysts.
E) prions.

Question 34

Disinfecting agents naturally produced by microorganisms are

A) aldehydes.
B) antibiotics.
C) halogens.
D) quaternary ammonium compounds.
E) triclosans.

Question 35

Quaternary ammonium compounds are disinfectants effective against

A) endospores.
B) mycobacteria.
C) nonenveloped viruses.
D) Pseudomonas aeruginosa.
E) enveloped viruses.

Question 36

The process of incineration is used for

A) sterilization.
B) degerming.
C) disinfection.
D) sanitization.
E) both disinfection and sanitization.

Question 37

A scientist develops a new medication that is a protein compound and that must be administered by injection. Which of the following would be the most effective and safest means of preparing a sterile solution of the new medication?

A) autoclaving
B) filtration
C) dilution with alcohol
D) lyophilization
E) ultraviolet irradiation

Question 38

What effect do aldehydes have on microbial organisms?

A) They disrupt cytoplasmic membranes.
B) They inhibit enzymes.
C) They damage nucleic acids.
D) They disrupt membranes and enzyme function.
E) They damage proteins and DNA.

Question 39

Which of the following antimicrobial agents is the most toxic to humans?

A) 70% alcohol
B) ethylene oxide
C) quaternary ammonium compounds
D) chloramines
E) iodophors

Question 40

Which of the following would be used to sterilize a mattress?

A) autoclaving
B) formaldehyde
C) ethylene oxide
D) heavy metals
E) non-ionizing radiation

Question 41

The phenol coefficient is one of the most widely used measurements of an antimicrobial agent's effectiveness.

Question 42

The microbial death rate is (constant/nonlinear/variable) over time.

Question 43

Gamma irradiation is effective for sterilization because it

A) damages molecules irreversibly.
B) is non-ionizing.
C) penetrates well.
D) destroys protein function, although DNA is undamaged.
E) is penetrating and causes extensive molecular damage.

Question 44

The decimal reduction time is the time required to kill all the microbes in a given sample.

Question 45

The process of freeze-drying microbes to preserve them is (denaturation/desiccation/lyophilization).

Question 46

Using an alcohol pad before taking a blood sample is an example of antisepsis.

Question 47

Disinfectants known as (alcohols/oxidizers/aldehydes) have the chemical group -CHO, which reacts with and damages both proteins and nucleic acids.

Question 48

By themselves, soaps have only degerming activity, not antimicrobial activity.

Question 49

Antimicrobial agents usually work best at high temperatures and high pH levels.

Question 50

Refrigeration is an effective germicidal method.

Question 51

Betadine contains what type of chemical agent?

A) alcohol
B) aldehyde
C) halogen
D) heavy metal
E) phenolic

Question 52

The cell walls of mycobacteria make them vulnerable to water soluble chemical agents.

Question 53

Natural antiseptics such as pine or clove oil are examples of antimicrobial compounds called (alcohols/phenolics/detergents).

Question 54

Formalin (37% formaldehyde) is used for

A) antisepsis.
B) disinfection.
C) sterilization.
D) sanitization.
E) both disinfection and sterilization.

Question 55

Protozoan cysts are resistant to many disinfection methods.

Question 56

Lysozyme is effective against nearly all disease causing agents.

Question 57

Slow freezing is more damaging to microbial cells than quick freezing.

Question 58

The compound ethylene oxide is used in

A) sanitization.
B) sterilization.
C) antisepsis.
D) degerming.
E) disinfection.

Question 59

Desiccation, a time-honored method of preserving food, is effective because the

A) heat of the process kills microbes.
B) freezing step of the process kills microbes.
C) salt concentration is too low to support metabolic function.
D) UV light used in the process of sun drying penetrates effectively.
E) water content is too low to support metabolic function.

Question 60

The lowest temperature that kills all cells in a broth in 10 minutes is known as the (microbial/terminal/thermal) death point.

Question 61

The physical removal of microbes is called (antisepsis/degerming/disinfection).

Question 62

The amount of time needed to sterilize materials using moist heat is (more/less) than the time needed to sterilize using dry heat.

Question 63

The (endospores/cysts/prions) are the infectious agents most resistant to antimicrobial agents or processes.

Question 64

Elements such as iodine, chlorine, and bromine are examples of (oxidizers/halogens/metals), which are the basis for many effective antimicrobial agents.

Question 65

The antimicrobial chemical pictured above in Figure 9.1 is a(n) (phenolic/surfactant/enzyme) compound found in many consumer products.

Question 66

Microbial growth in jellies is inhibited by the (acidic/hypotonic/hypertonic) condition of the food.

Question 67

Ultraviolet light penetrates (more/less) effectively than gamma rays.

Question 68

The deadliest, most contagious microbes are studied under conditions of (BSL-4/BSL-3/BSL-2/BSL-1) containment.

Question 69

A student is shopping for antibacterial hand cleansers and is trying to decide which one to buy. One is a "waterless" hand gel containing 70% isopropanol, the second is an "antibacterial" hand soap containing triclosan (a phenolic), and the third is a wipe that lists benzethonium chloride (a synthetic quaternary ammonium salt) as the active ingredient. Compare and contrast these cleansers in terms of the action of the antimicrobial ingredient and the level of disinfection (degerming, germistatic, germicidal).

Question 70

Compare and contrast the different uses of heat to reduce microbial contamination, including their relative efficacy.

Question 71

Long-term storage of milk is made possible by ultra-high-temperature (pasteurization/sanitization/sterilization).

Question 72

Some sterilization procedures do not kill all the microbes that may be present. Explain how these procedures may, for practical purposes, still be considered sterilization.

Question 73

What is the in-use test, and why is it more useful than other methods of evaluating disinfectants?

Question 74

Design an experiment to compare the effectiveness of a physical and a chemical method of disinfection.

Question 75

Heavy metal and oxidizing agent disinfectants damage (DNA/enzymes/membranes), interfering with microbial metabolism.