Chapter 7 The Control of Microbial Growth
HEPA filters are effective because they are designed to remove all airborne particulates including microorganisms down to
0.3 micrometers
any process that destroys the non spore forming contaminate on the inanimate object is sterlization
false
desiccation is a reliable form of sterlization
false
microorganisms placed in high concentrations of salts and sugars undergo lysis
false
ultraviolet light (UV) causes irreversible breaks in DNA strands
false
which of the following methods is used to preserve food by slowing the metabolic processes
freezing
which of the following could be used to sterilize plastic petri plates in a plastic wrapper
gamma radiation
which chemical disinfectant can be considered a sterilizing liquid agent when appropriately applied
glueteraldehyde
oxidizing agents include all of the following except
glutaraldehyde
in figure 7.1 the thermal death point for this culture is
the answer cannot be determined based on the information provided
in table 7.3 which disinfectant was most effective against salmonella
the answer cannot be determined based on the information provided
in table 7.1 which compound was the most effective against e.coli
the answers cannot be determined based on the information provided
which of the following best describes the pattern of microbial death
the cells in a population die at a constant rate
all of the following are methods of food preservation except
microwaves
in table 7.3 which disinfectant was a bactericidal
mortum
which of the following regarding antimicrobial control agents is false
most chemical agents can achieve sterility
bone and tendons for transplant are decontaminated by
supercritical fluids
in table 7.1 which compound was bactericidial
the answer cannot be determined based on the information given
in figure 7.1 the decimal reduction time (d value) for the culture, which is defined as the time to reduce a population by one log is approximately
10 minutes
which of the following treatments is the most effective for controlling microbial growth
140*c for 4 seconds
the most resistant of the bacterial endospores can withstand boiling for up to
20 hours
in figure 7.1 what is the thermal death time
60 mintues
which concentration of ethanol is most effective bactericide
70 %
in table 7.1 which compound was the most effective against staphylococcus
C..10
all of the following substances are effective against noneveloped viruses except
alcohol
which of the following regarding antimicrobial control agents is false
alcohols effectively inactivate nonenveloped viruses by attacking lipids
which graph in figure 7.2 best depicts the effect of placing the culture in an autoclave for 15 minutes
b
which of the following pairs of terms is mismatched
bacteriostatic - kills vegetative bacterial cells
which of the following pairs is mismatched
biguanide - sporocide
all of the following substances are used to preserve foods except
biguanides
which of the following disinfectants acts by disrupting the plasma membrane
bishphenols
all of the following are effective for destroying prions except
boiling
one advantage of chemical plasma is that it ____ but a disadvantage is ___
can be used for intricate surgical instruments; cannot be used on plastics
which of the following substances is used for surgical hand scrubs
chlorhexidine
which graph in figure 7.2 best depicts the effect of plain the culture at 7*c at time x
d
application of heat to living cells can result in all of the following except
decreased thermal death time
the preservation of beef jerky from microbial growth relies on which method of microbial control
desiccation
an agent used to reduce the number of bacteria on a toilet would be most accurately be called
disinfectant
in table 7.3 which disinfectant is the most effective at stopping bacterial growth
doom
which of the following chemical agents is used for sterilization
ethylene oxide
The pH of the medium has no effect on the activity of the disinfectant being applied.
false
which of the following results in lethal damage to nucleic acids
heat, radiation, and some chemicals
the most effective form of chlorine is which of the following
hypochlorous acid
an iodophor is an
iodine mixed with a surfactant
ethylene oxide
is a sterilizing agent
which of the following is a limitation of the autoclave
it cannot be used with heat labile materials
which one of the following is known to be most resistant to quaternary ammonium compounds
members of the genus pseudomonas
Which of the following is the best method to sterilize heat labile solutions
membrane filtration
all of the following factors contribute to hospital acquired infections except
none of the answers is correct all of these factors bay contribute to hospital acquired
which of the following does not achieve sterilization
pasteurization
disinfection of water is achieved by all of the following except
per acetic acid
the fate of e coli o157:h7 in apple cider held at 8*c for 2 weeks, with and without preservatives is shown below. which preservative is most effective
potassium sorbate + sodium benzoate
if you were preparing nutrient agar at home and did not have an autoclave what could you use to sterilize the nutrient agar
pressure cooker at 121*c for 15 minutes
Autoclaving is the most effective method of moist heat sterilization.
true
moist heat destroys organisms by denoting proteins
true
pseudomonas has been found growing in quaternary ammonium compounds (quats)
true
some antimicrobial chemicals are considered to be disinfectants and antiseptics
true
the thermal death time is the time needed to kill all the bacteria in a particular culture at a certain temperature
true
which of the following Pairs is mismatched
ultraviolet radiation - desiccation
a kitchen countertop has a spill of vegetable oil that was wiped up but a film remained. what should be the next step in disinfecting this surface
warm soapy scruby
