Chapter 2: Food Microbiology Flashcards

1
Q

Microbial population show a characteristic type of growth pattern, called?

A

exponential growth

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2
Q

little or no apparent growth for a period following the initial contact between the microbes and the environment

length of this phase varies with the condition of the microorganisms and the nature of the environment

A

stage 1: lag phpase

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3
Q

microorganisms are growing and dividing at the maximal rate

constant growth rate is observed

cells are in their healthiest state

A

stage 2: log phase (exponential phase)

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4
Q

no net increase or decrease in cell number

accumulation of wastes that are toxic and nutrient depletion

A

stage 3: stationary phase

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5
Q

decline in the number of viable cells

rate of death exceeds rate of growth

many of the numbers essential for survival are no longer available

A

stage 4: death phase

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6
Q

characteristic of the growth substrate

A

intrinsic factors

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7
Q

microorganisms require this type of moisture

A

free/available water

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8
Q

free water may be expressed as

A

water activity (aw)

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9
Q

amount of free or available water in a product, which can affect its shelf life, safety, and quality. It is measured on a scale from 0 (completely dry) to 1.0 (pure water)

A

water activity (aw)

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10
Q

ratio of the water vapor pressure over a food at equilibrium with the atmosphere above it to the water vapor pressure at the same temperature

A

water activity (aw)

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11
Q

aw of water is?

A

aw = 1.0

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12
Q

aw of a completely dehydrated food (e.g. crackers and powdered products)

A

aw = 0

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13
Q

Most bacteria, yeasts, and molds cannot grow. This is important for food preservation

A

aw = 6

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14
Q

an organism that grows in high concentration of salt

A

halophiles

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15
Q

salt tolerant organism

A

haloduric

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16
Q

organisms that can grow over a fairly wide range of Aw or solute concentrations

A

osmotolerant

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17
Q

aw of fresh foods

A

0.99

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18
Q

organic and inorganic compounds found in any substrate provide energy that supports microbial existence

release of energy consists of oxidizing one compound and reducing another

A

oxidation-reduction (redox) potential (Eh)

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19
Q

require positive Eh values

A

aerobes

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20
Q

will not start to grow until the redox has reached a critical maximum, much lower than facultative aerobes

A

anearobes

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21
Q

requires negative Eh values

A

anaerobes and facultative anaerobes

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22
Q

microorganisms need these nutrients to survive (conspim)

A

carbon, oxygen, nitrogen, sulfur, phosphorous, iron, magnesium

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23
Q

Water activity where yeasts can grow at lower aw levels compared to bacteria

A

aw = 0.88

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24
Q

Antimicrobial constituent in cloves, cinnamon, and sage

A

eugenol

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25
Q

Antimicrobial constituent in cinnamon

A

cinnamic aldehyde

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26
Q

Antimicrobial constituent in sage and oregano

A

thymol

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27
Q

Antimicrobial constituent in garlic

A

thymol

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28
Q

Antimicrobial constituent in mustard

A

allyl isothiocyanate

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29
Q

Antimicrobial constituent in eggs and milk

A

lysozyme

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30
Q

Antimicrobial constituent in milk

A

lactoperoxidase

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31
Q

imposed from outside

A

extrinsic factors

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32
Q

organisms with a narrow temperature range for growth

constant temperature

sa isang temperature lang makaka-survive (either cold or hot)

A

stenothermal

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33
Q

organisms growing from environments with greater natural variation of temperature

A

eurythermal

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34
Q

microorganisms that can grow at subzero to 20C with optimum at 10-15C

A

psychrophiles

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35
Q

psychrophiles are microorganisms that can grow at what temperature

A

subzero to 20C
optimum at 10-15C

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36
Q

microorganisms that can grow at and below 7C with optimum at 20-30C

A

psychrotrophs

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37
Q

psychrotrophs can grow at what temperature

A

at and below 7C
optimum at 20-30C

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38
Q

microorganisms that can grow at 20-45C with optimum at 30-40C

thrive best at rom temp and are more common spoilage organisms

A

mesophiles

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39
Q

mesophiles are. microorganisms that can grow best at what temperature

A

20-45C
optimum at 30-40C

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40
Q

microorganisms that can grow at and above 45C with optimum at 55-65C

cause of spoilage in thermally processed foods

when they multiply, they produce spores that are heat-resistant

A

thermophiles

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41
Q

thermophiles are microorganisms that can grow best at what temperature

A

at and above 45C optimum at 55-65C

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42
Q

two main gases that affect microbial activity

A

oxygen and carbon dioxide

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43
Q

Must have oxygen to survive and grow

A

obligate aerobe

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44
Q

Can grow with or without oxygen. They prefer oxygen but can switch to anaerobic processes if oxygen is absent.

A

facultative anaerobe

45
Q

organisms that can grow in the absence of oxygen

A

anaerobes

46
Q

some aerobic microorganisms that require only low levels of oxygen (2-10%) for growth

A

microaerophilic

47
Q

The oxygen level is typically reduced, while carbon dioxide is increased to slow down respiration and ripening. The environment is tightly controlled to ensure stability throughout storage.

A

controlled atmosphere (ca)

48
Q

A method where the concentrations of gases (mainly oxygen, carbon dioxide, and nitrogen) are continuously monitored and adjusted to maintain a precise atmosphere over time.

A

controlled atmosphere (ca)

49
Q

The atmosphere inside the package is modified (typically by reducing oxygen and increasing nitrogen and carbon dioxide) to slow down spoilage. The modified atmosphere is passive, relying on packaging materials to maintain the gas composition.

A

Modified Atmosphere (MA) Storage

50
Q

A one-time adjustment of the gas composition in a sealed package or container, without ongoing control or monitoring. Once the package is sealed, the atmosphere inside is not actively controlled further.

A

Modified Atmosphere (MA) Storage

51
Q

killing, inhibition, or removal of all microbes that may cause disease

used in inanimate objects

A

disinfection

52
Q

an agent that kills microbes but may also be harmful to human tissue

A

disinfectant

53
Q

general terms for an agent that kills microbes or inhibits their growth

A

antimicrobial agent (ama)

54
Q

low moisture and temp, high concentration of sugar and acid stimulates growth of _____

A

molds

55
Q

high moisture and temp, high concentration of sugar and acid stimulates growth of _____

A

yeast

56
Q

a process that kills or removes all forms of microbial life situation, results to complete absence of live microorganism whether in spore or vegetative form

A

sterilization

57
Q

sterilization that requires the use of water is known as

A

wet sterilization

58
Q

do not require the use of water

done to a point where there is dehydration and oxidation enough to destroy the bacterial cells

A

dry heat sterilization

59
Q

use of AMAs of substances that can prevent cell growth or even lead to cell death is suggested for disinfection and sterilization

A

chemicals

60
Q

radiation that can destroy intracellular structure of microorganisms are those with short wavelengths like the x-rays and the gamma rays

A

irradiation

61
Q

a microbial product or derivative that kills or inhibits growth of a susceptible microbe

A

antibiotic

62
Q

separation of microbial contamination from liquid

A

filtration

63
Q

causes the formation of thymine dimmers in DNA that inhibits DNA replication

A

raditation

64
Q

results from ingestion of pathogen-contaminated food

A

food-borne infection

65
Q

results from ingestion of foods containing performed microbial toxins

A

food-borne intoxication

66
Q

beneficial microbes: yeast fermentation in bread

or baker’s year is most useful in bread production

A

Saccharomyces cerevisiae

67
Q

causes gluten network to expand

A

co2

68
Q

formed after thorough kneading of flour, water, and yeast mixture

A

gluten network

69
Q

a beverage made from malted barley and water and flavored with the female flower of the hop plant

A

beer

70
Q

yeast added to the wort (mashed mixture of water, barley, and hops)

considered as the “top” yeast of the fermentation vessel in beer making

A

saccharomyces cerevisiae

71
Q

bottom yeast in making beer

A

saccharomyces carlsbergensis

72
Q

ingredients of beer

A

water
malt barley
yeast
flavored with the female flower (hop plant)

73
Q

results from the alcoholic fermentation of glucose and fructose contained in grapes and other fruits by yeast

A

wine

74
Q

used to facilitate fermentation of grape and other juices

A

saccharomyces cerevisiae, var. ellipsoides

75
Q

this type of wine derive its color from the red soluble pigment of the grape skin

fermentation temp: 20 ℃ to 32 ℃

A

red wines

76
Q

the skins and pulp of the grape are removed from the juice before fermentation begins

the temp of fermentation is lower than red wines (10-15C)

A

white wine

77
Q

bacteria utilized for the conversion of alcohol to acetic acid

allowed to grow aerobically on the surface of wine to produce malt vinegar

A

genus acetobacter

78
Q

products such as: cheese, butter, yoghurt, pickled vegetable products like sauerkraut (pickled cabbage), atchara, cucumber are from the fermentation of

A

acetic acid and lactic acid fermentation

79
Q

mold used for camembert cheese ripening

A

penicillium camemberti

80
Q

mold used for blue cheese ripening

A

p. roqueforti

81
Q

an organism able to grow at low temp

ex: food stored in the refrigerator

A

psychrotrophs

82
Q

an organism capable of growth at high temp

ex: foods kept warm for extended periods of time

A

thermophiles

83
Q

microbes that grow in acidic environment, responsible for spoiling products

ex: pickles, mayonnaise, and certain fruit juices

A

acidophiles

84
Q

infectious agent having a simple acellular organization with a protein coat and a single type of nucleic acid, lacks independent metabolism and reproducing only within living host cells

smallest known living organisms

ex: poliomyelitis, hepatitis a, viral gastroenteritis

A

virus

85
Q

organisms that resembles the characteristics of a virus and bacteria

contains both DNA and RNA, have typical bacterial cell walls

cannot be cultivated outside of living cells = obligate parasites

A

rickettssiae and chlamydia

86
Q

associated in the tissue of arthropods

ex: fleas, lice, ticks, and mites

transfer to humans or other animal is via bites from these blood-sucking arthropods

A

rickettsiae

87
Q

concern rickettsiae the causative agent for q-fever, can be excreted in the milk of an infected cow

can be trasnferred by a respiratory pathway in aerosols of infected dust and via the bite of tick

A

coxiella burnettii

88
Q

concern chlamydia is the causative agent transmitted to human in aerosols from infected poultry

A

chlamydia

89
Q

organism intermediate to virus and fungi in size

unicellular or multicellular prokaryotic organism

A

bacteria

90
Q

bacteria shape

spherical

A

cocci

91
Q

bacteria shape

rod-shaped

A

bacilli

92
Q

bacteria shape

helical

A

spirilla

93
Q

bacteria shape

curved

A

vibrios

94
Q

diverse group of organisms that may be unicellular or made up of tubular filaments (hyphae) and lacks chlorophyll

ex: yeast, mushrooms, molds

A

fungi

95
Q

multicellular and filamentous form of fungi on almost any substance used for food

seen on stable bread, cheese, fruit

musty odor and destroy the fresh flavor of food

A

molds

96
Q

molds produce a poisonous toxin called

A

mycotoxin

97
Q

a collective name for single-celled organism important in brewing and bread making

contamination if food created a slime on the surface, bubbles, and an alcoholic smell or taste

A

yeasts

98
Q

group of simple plants with unicellular reproductive structure

posses the green photosynthetic pigment, chlorophyll a

A

algae

99
Q

algae concerned associated with marine “red tides”

A

pyrrophyta/dinoflagellates

100
Q

unicellular eukaryotic microorganisms that lack cell walls

A

protozoa

101
Q

protozoa concerned in food microbiology

A

entamoeba hystolytica

102
Q

referred to as parasites

food- and water-borne helminthic infection is a common problem in situations with poor hygiene

A

helminthic eggs and larvae

103
Q

parasites found in game or pork

A

trichinella spiralis

104
Q

referred to as cod fish worm or seal worm

found in fish

A

anisakis spiralis

105
Q

microbial population show a characteristic type of growth pattern called

A

exponential growth

106
Q

little or no apparent growth for a period following the initial contact between the microbes and the environment

becomes acclimated to their environment

length of this phase varies with the condition of the microorganisms and the nature of the environment

A

stage 1: lag phase

107
Q

microorganisms are growing and dividing at the maximal rate

constant growth rate is observed

the chemical and physiologic properties of the population are most uniform

cells are in their healthiest state

A

stage 2: log phase (exponential phase)

108
Q

no net increase or decrease in cell number

characterize by accumulation of wastes that are toxic and nutrient depletion

A

stage 3: stationary phase

109
Q

decline in the number of viable cells

rate of death exceeds the rate of growth

factors essential for survival are no longer available

A

stage 4: death phase