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