Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

FDSC 442 > microbial spoilage and public health concerns > Flashcards

microbial spoilage and public health concerns Flashcards

1
Q

why is it important to understand microbial food spoilage?

A

to minimize economic losses and provide a high-quality food supply with adequate shelf-life

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

what do meat, poultry, and seafood have in common?

A

they are muscle foods, rich in nutrients (bacterial substrates), which allows extensive microbial growth and support the growth of bacterial pathogens

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

what are the differences between meat, poultry, and seafood?

A

They have different “original” microbiota leading to a different succession of microbial spoilage bacteria. they also differ in the handling and storage requirements, which also leads to a different microbial succession. they also differ in handling and storage requirements which also leads to a different microbial succession

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

under what conditions does contamination originate?

A
  1. natural: originating from the animal (GI tract, skin, feathers)
  2. originating from the processing environment
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

what is the first event in contamination?

A

attachment of bacterial cells to the meat surface

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

what bacteria is exceptionally good at attaching to meat surfaces?

A

pseudomonas

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

what is the best way to preserve meat?

A

having a very clean processing facility so that minimal numbers of bacteria attach to the surface of the meat

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

what is the significance of biofilms?

A

they are a major issue in food processing environments. they can form on almost any surface and can persist despite despite extensive cleaning efforts for years. once formed, bacteria can be 10- to 100- fold more resistant to sanitizers in comparison to planktonic cells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

____ of all meat and __ of all fish are lost due to microbial spoilage

A

one fourth

30%

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

what conditions affect the microbial succession in meat and fish?

A

conditions of slaughter, decontamination, and storage

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

In general, _____ bacteria, mostly ______ will dominate the microflora under cold aerobic conditions, and LAB will dominate vacuum-packaged products

A

gram-negative

enterbacteriaceae

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Pseudomonas inhibits ____and promotes ______

A

Shewanella

Listeria

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Pseudomonas utilizes glucose and produces ____ at higher rates than Shewanella

A

siderophores

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Pseudomonas also hydrolyses proteins and provides ____ to _____

A

amino acids

Listeria

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

what is the definition of spoilage?

A

consumers rejecting a food based on undesirable sensory characteristics. the definition is based on the consumer and will differ based on socio-economic factors

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

what does proteolytic spoilage result in?

A

putrid odors due to breakdown of amino acids

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

what does non-proteolytic spoilage result in?

A

sour odors

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

what is spoilage of canned foods due to?

A

improper process control, resulting in proliferation on mesophilic spore formers

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

what is the energy source of spoilage bacteria?

A

glucose

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

glucose is more rapidly metabolized by ____ bacteria than by ____ anaerobes

A

aerobic

facultative

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

If oxygen is present, ____ predominate in spoilage

A

Pseudomonas

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

what is the primary energy source of spoilage after glucose?

A

lactate, in both aerobic and anaerobic bacteria

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

what is the energy source after glucose and lactate?

A

amino acids

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

why are crustaceans like lobster and crayfish, kept alive until cooking?

A

their endogenous tissues enzymes in their hepatopancreas cause rapid postmortem muscle breakdown, independent of microbial processes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

what is the best type of evaluation for quality evaluation?

A

sensory evaluation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

the ideal spoilage indicator should…

A
  1. be absent or present in very low levels in fresh tissue
  2. be produced by the spoilage microflora
  3. increase with storage time
  4. correlate well with sensory analysis
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

What is meat traceability?

A

the ability to maintain credible custody of the identification of animals and their products from production to retail

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

the strategy for microbial control in meats is generally focused on _____ and _____

A

good hygiene

proper storage

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

methods for microbial control:

A
  1. harvest, or ship animals for slaughter with low contamination
  2. reduce the potential for transfer of microorganisms to carcasses, meat, and seafood from water and the environment
  3. apply safe and effective decontamination interventions
  4. apply processes such as heat, high pressure, irradiation, to reduce or eliminate microorganisms
  5. avoid cross-contamination
  6. store products at low temperature
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

how is the type and extent of microbial contamination determined on red meats?

A

determined by the hygiene of the animals before and during slaughter

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
31
Q

common microbes on fresh red meat are ____ rods and _____

A

gram-negative rods

micrococci

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
32
Q

examples of gram-negative rods and micrococci

A

Pseudomonas, enterobacteriaceae, acinetobacter, staphylococcus, micrococcus, coryneforms, and fecal streptococci

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
33
Q

what bacteria are present in lower populations on red meat?

A

LAB, bacillus, and clostridium spores

34
Q

what species of microorganisms are the dominating spoilage microorganisms in red meat?

A

pseudomonas spp.

35
Q

what happens when meat is immediately vacuum-packed?

A

gram-positive bacteria will dominate the population

36
Q

Remember, microbes like to use ____ before ____ for energy production, and amino acid degradation leads to more signs of spoilage

A

glucose

amino acids

37
Q

what pre-slaughter factor leads to faster degradation of amino acids in red meat?

A

the animal being stressed or exercised before slaughter.

38
Q

____ meats spoil more slowly than _____ meats because of higher initial contamination, larger surface, area, cross-contamination during grinding, and the release of fluids for bacterial growth media due to cells rupturing during grinding.

A 
intact meats (steak)
comminuted meats (ground beef)
39
Q

processed meats have lower ___ due to added salt

A

water activity

40
Q

spoilage by what kind of bacteria is limited in processed meats?

A

gram-negative psychotropic bacteria

41
Q

spoilage by what kind of bacteria is prevalent in processed meats?

A

lactobacilli (anaerobic) or micrococci (aerobic)

42
Q

examples of processed meats:

A
  1. bologna
  2. cooked or fermented sausage
  3. cold-cuts
43
Q

sliming is the result of what bacteria?

A

growth of yeasts, lactobacillus, enterococcus, and B. thermosphacta

44
Q

greening is the result of waht bacteria?

A

production of hydrogen peroxide by lactobacillus viridescens, streptococcus, or leuconostoc

45
Q

how do dry-cured meats spoil?

A

presence of yeasts or molds that tolerate extremely low water content

46
Q

most of the microbiota associated with poultry is acquired from which regions of the bird?

A

bird’s skin, feathers

47
Q

bacterial populations associated with the carcass at the end of processing are _____ bacteria

A

predominantly gram-negative

48
Q

gram-negative bacteria in carcasses at the end of processing?

A

Acientobacter/ morazella, enterobacteriaceae, and pseudomonas

49
Q

during refrigeration storage, ____ spp. group becomes predominant

A

pseudomonas

50
Q

steps of processing poultry:

A
  1. stunning/ killing / bleeding
  2. Scalding
  3. picking
  4. evisceration
  5. chilling
51
Q

stunning/killing

A

Birds are placed onto moving shackles and are stunned with electricity or low oxygen

52
Q

scalding

A

birds are immersed in hot water to ease the removal of feathers

53
Q

picking

A

the feathers are removed by placing the bird in a picker, containing rubber fingers to grab the feathers and full them out. this process aerosolized bacteria and can spread them to other carcasses

54
Q

evisceration

A

Intestinal tract is mechanically removed. this could sometimes damage thigh and back muscles resulting in tissue rupture and more nutrients being available for spoilage. intestines could also rupture leading to fluid leakage into the carcass which increases bacterial load

55
Q

chilling

A

carcasses chilled to reduce microbial growth which improves shelf-life and food safety. air chilling is the most common method

56
Q

spoilage bacteria metabolizes _____ first, which leads to a CFU population of _____

A

glucose

10^8 CFU/cm^2

57
Q

the most common spoilage organism at refrigeration temperatures is ______ but ____ can also be involved in spoilage

A

Pseudomonas spp.

yeasts

58
Q

what are foodborne pathogens associated with seafood?

A

salmonella, Clostridium botulinum, aeromonas, S. aureus, L. monocytogenes, vibrio cholerae, vibrio parahaemolyticus, and vibrio vulnificus

59
Q

aqua-cultured fish tend to have a higher ______ than their wild counterparts

A

bacterial load

60
Q

What are biogenic diamines?

A

compounds produced by decarboxylation of specific free amino acids, which are produced by postmortem fish or shellfish tissue

61
Q

how does decarboxylation occur?

A

via the release of decarboxylase from the various microorganisms growing on the food product

62
Q

fish muscle is naturally rich in free ____, and this increases even more after the fish dies

A

amino acids

63
Q

What are some biogenic diamines?

A

histamine, cadaverine, and putrescine

64
Q

_____ is not destroyed by cooking, so even properly cooked spoiled fish can result in poisoning

A

histamine

65
Q

what is a consequence of nitrite being used in cold-smoked fish products that aren’t fresh enough?

A

putrescine and cadaverine will react with nitrite, producing carcinogens

66
Q

consuming biogenic amines can cause what type of food poisoning?

A

scomboid food poisonings (a disease due to the ingestion of contaminated food, mainly in fish)

67
Q

symptoms of scombroid food poisoning?

A

flushed skin, headache, itchiness, blurred vision, abdominal cramps, and diarrhea

68
Q

how long can scombroid food poisoning last?

A

2 days

69
Q

how fast do scombroid food poisoning symptoms come on?

A

10-60 minutes after eating

70
Q

what are the causes of scombroid food poisoning?

A

fish being improperly stored, which results in microbial growth, resulting in the production of biogenic amines, such as histamine

71
Q

_____ is the main natural chemical responsible for true allergic reactions, so the symptoms are almost identical to a food allergy

A

Histamine

72
Q

what can be taken to alleviate symptoms of scombroid food poisoning?

A

anti-histamines

73
Q

____ are the most exportable seafood product in the world

A

Shrimp

74
Q

what are pathogenic vibrios?

A

gram-negative bacteria that cause illness

75
Q

____ can attach to and colonize the exoskeletons of shrimp

A

pathogenic vibrios

76
Q

what organisms are responsible for refrigerated shrimp spoilage?

A

pseudomonas and aeromonas

77
Q

what kind of contamination of growing ponds where shrimp are produced, is most common?

A

fecal contamination, coliforms, and salmonella are common in shrimp rearing environments

78
Q

____ are filter feeders that can concentrate the native water microbiome

A

Oysters

79
Q

why is it that consuming oysters raw, is problematic?

A

eating raw oysters is associated with several outbreaks

80
Q

what other type of shellfish besides oysters, is also problematic to eat raw?

A

mussels - concentrate bacteria

FDSC 442 (13 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions