12 - Microbial Spoilage and Public Health Concerns Part 1

Question 1

can spoiled food still be safe?

Answer 1

yes

Question 2

how do meat, poultry and seafood differ?

Answer 2

their original microbiotas, handling, and storage requirements

Question 3

what’s the bacteria population like in muscle tissue of healthy live animals?

Answer 3

absent, undetectable, or present in very low numbers

Question 4

how is contamination categorized?

Answer 4

• natural

- external

Question 5

describe natural contamination

Answer 5

originating from the animal (GI tract, skin, feathers)

Question 6

describe external contamination

Answer 6

originating from processing environment

Question 7

the first event in meat contamination is:

Answer 7

attachment of bacterial cells to meat surface

Question 8

what bacteria is particularly good at attaching to meat?

Answer 8

Psuedomonas

Question 9

why are biofilms problematic?

Answer 9

they are PERSISTANT despite extensive cleaning efforts and can be 10 to 100 fold more resistant to sanitizers

Question 10

how much meat and fish are lost due to microbial spoilage

Answer 10

• quarter of meat-

- 30% of fish

Question 11

describe interaction between Pseudomonas, Shewanella, and Listeria

Answer 11

• Pseudomonas inhibits Shewanella by using the same substrates faster
• Pseudomonas promotes Listeria by hydrolysing proteins

Question 12

define spoilage

Answer 12

consumers rejecting a food based on undesirable sensory characteristics

Question 13

proteolytic spoilage leads to what kind of odors

Answer 13

putrid

Question 14

non-proteolytic spoilage results in what kind of odors

Answer 14

sour

Question 15

microbial spoilage leads to….

Answer 15

• off flavors
• off odors
• off textures
• discoloration
• slime

Question 16

what is the energy source of spoilage bacteria?

Answer 16

glucose

Question 17

what is the predominant spoilage organism when oxygen is present?

Answer 17

Pseudomonas

Question 18

what is the next primary energy source after glucose? and then after that?

Answer 18

lactate; amino acids

Question 19

why are crustaceans kept alive until cooking?

Answer 19

they have endogenous enzymes that cause rapid postmortem muscle breakdown independent of microbial proteases

Question 20

how is spoilage evaluated?

Answer 20

• sensory, but it’s subjective

- microbial analysis

Question 21

what attributes does an ideal spoilage indicator have? (4)

Answer 21

• be absent or present in very low levels in fresh tissue
• be produced by spoilage microflora
• increase with storage time
• correlate well with sensory analysis

Question 22

what is the main concern of food spoilage with regard to common food-processing treatments?

Answer 22

that AMR bacteria may have higher resistance to these treatments

Question 23

what is traceability?

Answer 23

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

Question 24

where does traceability do well and where does it get muddled?

Answer 24

good: from a single animal
muddled: compound products (like ground beef)

Question 25

what are the dominating spoilage microorganisms in red meat at cold temps?

Answer 25

Psedomonas

Question 26

how does a stressed animal affect spoilage?

Answer 26

• decreases glucose in tissue

- leads to faster degradation of amino acids

Question 27

what are the dominant microorganisms that spoil ground meat?

Answer 27

still Pseudomonas, but LAB can dominate the interior given anaerobic conditions

Question 28

what spoils processed meats?

Answer 28

lower-water-activity tolerating bacteria:

• lactobacilli
• micrococci

Question 29

how do processed meats spoil?

Answer 29

develop slime, souring, or geening

Question 30

what microorganism is slime production associated with?

Answer 30

yeasts, Lactobacillus, Enterococcus, Streptococcus, Lueconostoc

Question 31

what causes spoilage of dry-cured meats?

Answer 31

yeasts or molds that tolerate extremely low water content

Question 32

what spoilage microorganism predominates poultry during refrigeration?

Answer 32

Pseudomonas spp. yeasts can also be involved.

Question 33

what are the steps of processing poultry?

Answer 33

• stunning/killing/bleeding
• Scalding
• picking
• evisceration
• chilling

Question 34

what methods are used for chilling of poultry?

Answer 34

• wet (gains weight)

- dry (loses weight)

Question 35

which has a higher bacterial load: aquacultured or wild fish?

Answer 35

aquacultured

Question 36

what foodborne pathogens are associated with seafood?

Answer 36

Salmonella, C. Botulinum, Aeromonas, S. aureus, L. monocytogenes, Vibrio cholerae, Vibrio parahaemolyticus, and vibrio vulnificus

Question 37

list some biogenic diamines

Answer 37

• histamine
• cadaverine
• putrescine

Question 38

how are biogenic amines produced?

Answer 38

decarboxylation of specific free amino acids by decarboxylase

Question 39

consuming biogenic amines can cause what condition?

Answer 39

Scombroid food poisoning

Question 40

what amino acid leads to the production of histamine by decarboxylase?

Answer 40

Histidine

Question 41

what can happen in cold-smoked fish products?

Answer 41

putrescine and cadaverine will react with nitrites to produce carcinogens

Question 42

what are the symptoms of Scombroid food poisoning?

Answer 42

almost identical to food allergy

Question 43

problem microorganisms associated with shrimp?

Answer 43

• Vibrios in raising waters
• coliforms
• Salmonella
  refrigerated:
• Pseudomonas
• Aeromonas

Question 44

problem microorganisms associated with shellfish?

Answer 44

• vibrios in environments
• oysters concentrate stuff
• mussels also concentrate stuff