Chapter 4: Microbial Growth Control Flashcards

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1
Q

sepsis

A

bacterial contamination

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2
Q

example of sepsis

A

severe infection

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3
Q

asepsis

A

absence of significant contamination (normal microbiota)

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4
Q

aseptic surgery techniques prevent

A

microbial contaminatoin of wounds

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5
Q

sterilization

A

removing and destroying all microbial life

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6
Q

why is sterilization not always effective

A

come bacteria can resist sterilization via endospore

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7
Q

commercial sterilization

A

killing C. botulinum endospores from canned goods

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8
Q

commercial sterilization focuses on

A

time, temperature, presure

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9
Q

disinfection

A

destroying harmful microorganisms

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10
Q

antisepsis

A

destroying harmful microorganisms from living tissue

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11
Q

degerming

A

mechanical removal of microbes from limited area

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12
Q

sanitization

A

lowering mocrobial counts on eating utensils to safe levels

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13
Q

biocide (germicide)

A

treatments that kill microbes

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14
Q

biocide used for

A

BSL3 or 4 to fight back against biowarfare

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15
Q

bacteriostasis

A

inhibiting microbes (not killing them)

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16
Q

methods of bacteriostasis

A

fridge, oven, microwave, freezing

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17
Q

most critical part of exponential death rate

A

first minute

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18
Q

plotting exponential death rate logarithmically results in

A

straight line

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19
Q

effectiveness of treatment depends on

A

number of microbes
environment (organic matter, temp, biofilms)
time of exposure
microbial characteristics

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20
Q

the higher the population, the

A

longer it will take to kill

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21
Q

actions of microbial control agents

A

alteration of membrane permeability
damage to proteins
damage to nucleic acids

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22
Q

what denatures enzymes

A

heat

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23
Q

thermal death point (TDP)

A

lowest temp at which all cells in liquid culture are killed in 10 minutes

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24
Q

thermal death time (TDT)

A

minimal time to kill all bacteria in liquid culture at a particular temperature

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25
Q

decimal reduction time (DRT)

A

minutes to kill 90% of population at a given temperature

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26
Q

what denature proteins

A

moist heat

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27
Q

3 exampless of moist heat

A

boiling, free flowing system, autoclave

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28
Q

autoclave

A

steam under pressure; 121 degrees C at 15psi for 15 min

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29
Q

in order for an autoclave to kill all organisms and endospores, steam must

A

contact all surface of the item - larger items require longer time

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30
Q

what iss used to indicate sterility

A

test strips

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31
Q

pasteurization reduces

A

spoilage organisms and pathogens

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32
Q

pasteurization treatments

A

63 degrees C for 30 min
HTST
UHT

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33
Q

high temp short time

A

72 degrees C for 15 seconds

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34
Q

ultra high temp

A

140 degrees C for 4 seconds

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35
Q

what type of organisms survive pasteurization

A

thermoduric organisms

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36
Q

dry heat sterilization kills by

A

oxidation

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37
Q

3 examples of dry heat

A

flaming, incineration, hot-air sterilization

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38
Q

filtration

A

passage of substance through screen-like material

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39
Q

filtration used for

A

heat-sensitive materials

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40
Q

HEPA filters

A

high-efficiency particulate air filters remove microbes > 0.3 micrometers (some viruses)

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41
Q

treating microbes with low temp has

A

bacteriostatic effect

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42
Q

3 examples of low temp treatment

A

fridge, deep freeze, lyophilization

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43
Q

what denatures proteins other than heat

A

high pressure

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44
Q

desiccation

A

absence of water prevents metabolism

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45
Q

osmotic pressure uses

A

salts/sugars to create hypertonic environment to cause plasmolysis

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46
Q

ionizing radiation

A

ionizes water to creat reactive hydroxyl radicals

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47
Q

3 examples of ionizaing radiation

A

x-rays, gamma rays, electron beams

48
Q

ionizing radiation damages DNA by

A

causing lethal mutations

49
Q

2 examples of nonionizing radiation

A

UV, 260 nm

50
Q

nonionizing radiation damages DNA by

A

creating thymine dimer

51
Q

microwaves kill by

A

heat, but doesnt kill to an acceptable level

52
Q

principles of effective disinfectant

A

concentration, what type of organic matter, pH, time

53
Q

use-dilution test

A

metal cylinders dipped in test bacteria - placed in disinfectant (10min at 20C) - transfer to culture media to determine if any survived

54
Q

if use-dulation test indicates a disinfectant is ineffective, what should happen

A

increase concentration, time, or heat

55
Q

disk-diffusion test

A

evaluates efficacy of chemical agents - filter paper disks soaked in chemical and placed on culture - measure zone of inhibition

56
Q

phenol and phenolics work by

A

injure lipids of plasma membrane causing leakage, denature enzymes

57
Q

phenolics used in

A

environmental surfacess, instruments, skin surfaces, mucous membranes

58
Q

bisphenol

A

two phenol groups connected by a bridge

59
Q

bisphenols work by

A

disruption of plasma membrane

60
Q

bisphenols used in

A

disinfectant hand soaps and skin lotions

61
Q

2 examples of bisphenols

A

hexachlorophene and triclosan

62
Q

biguanides work by

A

disrupting plasma membrane

63
Q

example of bugianide

A

chlorhexidine

64
Q

biguanide used in

A

surgical hand scrubs

65
Q

examples of halogens

A

iodine, chlorine

66
Q

iodine works by

A

impair protein synthesis and alter membrane, oxidizing agent

67
Q

iodine tincture

A

solution in aqueous solution

68
Q

iodine iodophor

A

combined with organic molecule

69
Q

cholrine works by

A

oxidation - shuts down cellular enzyme systms

70
Q

bleach is

A

hypochlorous acid HOCl

71
Q

chloramine is

A

chlorine + ammonia

72
Q

chlorines used to

A

disinnfect dairy equipment, eating utensils, household items, glassware

73
Q

alcohol works by

A

dennature protein and dissolves lipids

74
Q

alcohol has no effect on

A

endospores or nonenveloped viruses (ebola)

75
Q

2 examples of alcohol

A

ethanol, isopropyl - requires water for application

76
Q

alcohol used for

A

thermometers, swabbing skin before injection

77
Q

heavy metals and their compounds work by

A

denature enzymes and proteins

78
Q

oligodynamic action

A

very small amounts exert antimicrobial activity

79
Q

four heavy metals

A

silver, mercury, copper, zinc

80
Q

silver nitrate

A

prevents ophthalmia neonatorum

81
Q

mercuric chloride

A

prevents mildew in paint

82
Q

copper sulfate

A

algicide

83
Q

zinc chloride

A

mouthwash

84
Q

3 types of surface-active agents

A

soap, acid-anionic sanitizers, quats

85
Q

soap

A

degerming, emulsification

86
Q

acid-anionic sanitizers

A

anions react with plasma membrane

87
Q

acid-anionic sanitizers used in

A

dairy and food processing industries

88
Q

quaternary ammonium compunds

A

cations are bactericidal - denature proteins, inhibit enzymes, disrupt plasma membrane

89
Q

quats used in

A

antiseptic for skin, instruments, utensils, rubber goods

90
Q

3 chemical food preservatives

A

sulfur dioxide, organic acids, nitrates/nitrites

91
Q

sulfur dioxide

A

prevents wine spoilage

92
Q

organic acids work by

A

inhibit metabolism

93
Q

3 examples of organic acids that prevent mold

A

sorbic acid, benzoic acid, calcium propionate

94
Q

nitrates and nitrites prevent

A

endospore germination

95
Q

nitrates and nitrites used in

A

pork products

96
Q

2 examples of antibiotics

A

bacteriocins, nisin/natamycin

97
Q

bacteriocins

A

proteins produced by one bacterium that inhibits another

98
Q

nisin and natamycin

A

prevent spoilage of cheese

99
Q

aldehydes work by

A

inactivate proteins by cross-linking with functional groups

100
Q

aldehydes used for

A

preserving specimens and medical equipment

101
Q

3 examples of aldehydes

A

formaldehyde, ortho-phthalaldehyde, glutaraldehyde

102
Q

glutaraldehyde

A

one of few liquid-sterilizing agents

103
Q

chemical sterilization

A

gaseous sterilants cause alkylation by c

104
Q

alkylation

A

replacing H of a chemical group with a free radical

105
Q

chemical sterilization works by

A

cross-links nucleic acids and proteins

106
Q

chemical sterilization used for

A

heat sensitive materials

107
Q

example of chemical sterilization and where it comes from

A

ethylene oxide - ripening fruit

108
Q

plasma

A

fourth state of matter, electrically excited gas

109
Q

plasma works by

A

free radicals destroy microbes

110
Q

plasma used for

A

tubular instruments

111
Q

supercritical fluids

A

CO2 with gasoues and liquid properties

112
Q

supercritical fluids used for

A

medical implants

113
Q

peroxygens and oxygen work by

A

oxidizing agents

114
Q

peroxygens and oxygen used for

A

contaminated surgaces and food packaging

115
Q

examples of peroxygens and oxygen

A

O3, H2O2, peracetic acid