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WorksheetsControl of Microbial Growth
Total questions: 60
Worksheet time: 30mins
Pasteurization:
Eliminates all vegetative forms of microbes
Destroys pathogens without altering the taste of the food
Sterilizes culture media
Eliminates endospores
Pyrimidine dimers are removed using:
Photolyase
Nucleotide excision repair
the SOS system
All of these
Pyrimidine dimers only occur:
when two adjacent T's stick together
when two adjacent C's stick together
when two adjacent A's stick together
when two adjacent T's OR C's stick together
Soaps and detergents are examples of:
Phenols
Tinctures
Halogens
Surface active agents
At the same temperature and time which treatment would be more effective?
Dry heat
Moist heat
When subjected to heat or antimicrobial chemicals most bacteria usually:
immediately die
accelerate growth into a log phase
form endospores
die at a constant rate
All of the following are food preservatives, except:
Formaldehyde
Sulfur dioxide
Calcium proprionate
Nitrates
The pasteurization technique used for immediate cold-storage products (AKA milk, yogurt, ice cream…) is termed _________________________.
HTST
UHT
Chemical sterilization
Biocidal pasteurization
Which of the following is most resistant to microbial control methods?
Prions
Gram positive bacteria
Gram negative bacteria
Acid-fast bacteria
The most common physical method of microbial control is:
heat
cold
osmotic pressure
filtration
The most effective concentration of alcohol to control bacterial growth is:
50%
70%
100%
85%
The Thermal Death Point is:
the lowest temperature at which all the microbes in a liquid culture will be killed in 10 minutes
the length of time required to kill all bacteria in a liquid culture at a given temperature
the length of time in which 90% of a bacterial population will be killed at a given temperature
the target temperature for autoclaving
All bacteria have 2 thermal death points.
True
False
Which of the following bacteria have 2 thermal death points?
Clostridium tetani
Bacillus megaterium
Bacillus anthracis
All of these.
Using a highly concentrated bacteriostatic can cause bacterial death.
True
False
The sticky carbohydrate-based component of a biofilm that allows bacteria to resist the actions of disinfectants is termed the _______________________.
Cell wall
Ribosome
Nucleoid
Glycocalyx
The term that means free from microbes is:
septic
aseptic
microstatic
clean
Filtration is used to:
Remove microbes from air
Sterilize heat sensitive solutions
Filter out bacteria, viruses, and even large proteins
All of the these
Dimers are produced by:
UV radiation
Alcohol
Antibiotics
ATP synthase
Bacteria are more sensitive to acidic environments than fungi.
True
False
Which of the following would be expected to influence the effectiveness of an antimicrobial treatment?
Number of microbes present
Presence of organic matter
The length of time the microbes are exposed to the treatment
All of these
Nonionizing radiation at a wavelength of _______nm damages DNA by creating ___________.
130; thymine dimers
130; guanine dimers
260; guanine dimers
260; thymine dimers
Which disinfectant was the LEAST effective against Staphylococcus?
A
B
C
D
____________________ organisms are those that survive pasteurization processes.
pasteurogenic
thermoduric
tolerant
pathogenic
Boiling at ___________ kills most endospores of bacterial pathogens, many viruses, and fungi within 10 mins.
37C
25C
100C
200C
Antimicrobial agents are generally made more effective by:
high pH
low temperature
high temperature
presence of organic matter
Heavy metals (Ag, Hg, Cu, Zn) and their compounds work by ________________.
oligodynamic action
denaturation
lysing the cell membrane
both oligodynamic action & denaturation
Salts and sugars can be used to preserve foods because they cause:
osmotic plasmolysis
osmotic lysis
acidosis
alkalosis
O-phenylphenol, hexachlorphene, and triclosan are all examples of:
phenols
alcohols
halogens
surface-active agents
Which of the following methods would be most likely to kill endospores?
boiling
autoclaving
disinfecting
filtration
Alcohol evaporates quickly. This is called:
volatility
disintegration
degeneracy
antisepsis
Nosocomial infections are those acquired from:
hospitals
nursing homes
outpatient clinics
all of these
Ana is at a restaurant and finds dried food on her fork. What method of disinfection should have been completed?
sanitization
antisepsis
biocide
commercial sterilization
Before injecting a patient, you should __________ the skin.
disinfect
degerm
sanitize
sterilize
Eric is adding a fungicide to his pool. His goal is to ______ fungus.
limit
stop growth of
kill
increase growth of
In most cases, once a bacteriostatic agent is removed, growth will resume.
True
False
Alcohol is a bacteriostatic agent.
True
False
Alcohol is both a disinfectant and an antiseptic.
True
False
In order to effectively kill endospores, virus particles, and fungi, autoclaves must:
Reach 121ºC at 15 psi for 30 min
Reach 121ºC at 15 psi for 15 min
Reach 150ºC at 25 psi for 30 min
Reach 150ºC at 15 psi for 15 min
Michelle wants to clean a dirty toilet. She should probably use a:
disinfectant
degermer
antiseptic
biocide
Before surgery, Gary needs to complete a skin-prep with Betadine. This is a form of:
antisepsis
disinfection
antibiotic
stasis
Which of the following does NOT achieve sterilization?
dry heat
pasteurization
autoclave
supercritical fluids
Which of the following results in lethal damage to nucleic acids?
heat
radiation
certain chemicals
all of these
Gram positive organisms are more resistant to control agents than Gram negative.
True
False
Soap can be used as a surface active agent because it:
Degerms and emulsifies lipids
Uses anions to react with the plasma membrane
Uses cations to denature proteins
Contains quats
What is the only way to be sure that all microbes have been destroyed?
Sterilization
Disinfection
Antisepsis
Incineration
In the ____________________ method, filter paper disks are soaked in a chemical and placed on a culture to evaluate the efficacy of chemical agents.
Paul Ehrlich
Kinyoun
Use-Dilution
Disk-Diffusion
The symbol indicates that ___________ has been used to reduce microbes.
Desiccation
Irradiation
Pressurization
Pasteurization
When bacterial populations are heated, they usually die at a constant rate of 90% per minute. If 1,000,000 microbes are heated for 2 minutes, how many remain?
100,000 microbes
10,000 microbes
1,000 microbes
100 microbes
Refrigeration and incubation are both:
Long-term preservation techniques
Short-term preservation techniques
Low temperatures are:
bactericidal
bacteriostatic
Best treatment for swimming pool bacteria?
chlorine
o-phenylphenol
chlorhexidine
sulfur dioxide
Oldest known antiseptic (ex: betadine)
iodine
chlorine
chlorine dioxide
triclosan
Used to prevent mold growth in cosmetics:
hexachlorophere
aldehyde
organic acids
iodine
All-purpose cleaner found in Lysol:
O-phenylphenol
iodine
chlorine dioxide
bleach
Prevents the souring of wine:
sulfur dioxide
hexachlorophere
iodine
aldehydes
Erica is scrubbing-up before surgery. She should use:
Chlorhexidine
Hexachlorophere
Iodine
Alcohol
KiddieAcademy is planning on sanitizing the playroom. Which is the best disinfectant?
triclosan
chlorhexidine
hexachlorphene
aldehyde
Used to fumigate large buildings:
aldehyde
plasma sterilization
chlorine dioxide
sulfur dioxide
Used for embalming:
bleach
triclosan
aldehydes
tetracycline
