Brainscape's Knowledge GenomeTM

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


See full index

Microbiology Lab > Food Microbiology Unit 5 > Flashcards

Food Microbiology Unit 5 Flashcards

1
Q

Bacillus cereus etiology

A
  • gram + rod
  • spore forming
  • facultative aerobic
  • motile most
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Bacillus cereus types of infection

A

emetic and diarrheal

  • emetic means onset of symptoms much faster
  • –caused by ETE toxin
  • –30 min- 6hours
  • –nausea, vomiting, abdominal cramps
  • – usually STARCHY
  • Diarrheal
  • –6-15 hours
  • –can be broken down by heat
  • – watery diarrhea, abdominal cramps
  • –usually with protein
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Bacillus cereus development of disease

A
  • infection = becteri
  • intoxication = toxin
    • toxin is heat stable
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Bacillus cereus foods and reservoir

A

foods in temperature danger zone are a big proponent
-FRIED RICE = emetic
inadequate refrigeration and reheating
Reservoir: soil and vegetation
-Infectious does: 100,000 to 100,000,000 cells (infection)

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

Bacillus cereus growth characteristics

A

temp: mesophilic
— optimum: 28-35 degree C
— Range: 4-48 degree C
pH: tolerate 4.9-9.3
—- more rugged because of endospores
aw: 0.95, halophilic
–tolerates 7.5% salt concentration

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

Bacillus cereus epidemiology

A

year round,
food: beef, turkey, RICE, beans, veggies
fringens= “break into pieces” - gas gangrene

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

Clostridium pefringens etiology

A

Gram + rod, endospore forming, non-motile, AEROTOLERANT anaerobe (doesn’t use o2)

  • -Type A = CPEnterotoxin, diarrhea
    • Type C = b toxin necrotizing colitis
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Clostridium pefringens growth requirements

A 
temp range: 15-55 degree C
--- optimum: 43-47C
pH: range: 5-9
--- optimum: 5-6
aw: 0.96
--salt concentration: 5%
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Clostridium pefringens characteristics of disease

A

-causes toxicoinfection
Two forms:
-Gastroenteritis: watery diarrhea and mald abdominal cramps
-Enteritis necrotitis: abdominal pain and distension, diarrhea, vomiting, and patchy necrosis of small intestine
—- can be fatal
Incubation period: 16 hours
Duration: 12-24 hours

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

Clostridium pefringens pathogenesis

A

-Doubling time is 10 minutes under optimum growing conditions
-enterotoxin is released when vegetative cell is lysed- after sporulation
-pig-bel disease involves the production of beta toxin
Infectious does: 1,000,000 cells or spores

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

Clostridium pefringens food and reservoir

A
  • requires high protein food because it can only synthesize 13 of the 20 amino acids
  • commonly found in raw meat and poultry
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Clostridium pefringens epidemiology

A

commons foods: beef, poultry, and pre-cooked foods

-occurs where food is prepared in large quantities and left warm

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

Clostridium botulinum four forms

A

infant, wound, food-borne, weaponized

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

Clostridium botulinum LD50

A

lethal dose is 50% of people

= 0.4 nanograms/kilogram of body weight

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

Clostridium botulinum development of disease

A

INTOXICATION
Incubation period: 12-36 hours
Signs and symptoms: nausea vomiting, visual impairment, loss of normal mouth and throat function
–descending flaccid paralysis
Cause of death: respiratory failure
Initial treatment: antibody/antitoxin
-inhibits release of acetylcolene in the muscle tissue which means the neurotransmitters never get the message

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

Clostridium botulinum prevention and control

A
  • endospores very resistant to radiation
  • EDUCATION to improve canning methods
  • heating canned foods for 10 mins before eating- boiling
  • never give children honey
17
Q

Clostridium botulinum food, reservoir and transmission

A

soil, water, and sewage
Transmission= ingestion of toxin in contaminated food,
-contamination of a wound
-ingestion of endospores by infant
-found in fish, meats, HONEY, and veggies

18
Q

Listeria monocytogene etiology

A

gram + rod, flagella all over, psychotropic: grows from 0-45 degrees C

19
Q

Listeria monocytogene growth requirements

A

pH: grows at 4.4 or greater. Can still survive t lower pH
aw: grows at 0.93 and above. Survives at 0.83
Salt: grows in moderate salt concentrations. 6.5%, halophile

20
Q

Listeria monocytogene foods

A

ready to eat foods = problem

21
Q

Listeria monocytogene pathogenesis

A

–Can swim into neighboring cells
– lives in phagocytes, no immunity function can kill it
-TWO TYPES:
-Diarrheal- intestines, most people do not experience any illness, incubates in a few hours to 3 days. Fever, muscle aches, nausea, vomiting
-invasive- brain and placenta, incubates anywhere from 3 days to 3 months. Initial symptoms and same as diarrheal but later is spreads to nervous system leading to headache, stiff neck, confusion, convulsions, and meningitis
-Case fatality rate is 15-30%
-

22
Q

Listeria monocytogene spread of infection/ food/

A

ready to eat foods = problem

  • raw or unpasteurized milk
  • cheeses-especially soft cheese
  • ice cream
  • raw veggies
  • raw meat and poultry
  • fermented raw meat sausages and hot dogs and deli meat
23
Q

Listeria monocytogene prevention and control

A

Reservoir: moist environments, soil and decaying plant and fecal matter
-Sources of contamination: food workers, incoming air, raw materials and food-processing surfaces

24
Q

Listeria monocytogene dose

A
  • Infectious dose: depends on health of human, varies form 0.3 CFU to 10^9 CFU
  • Why is this a new microbe?
    • more refrigeration, less competition
25
Q

Staphylococcus aureus etiology

A

vegetative cells = heat senswitive

  • toxin = heat resistant
  • clusters of gram + spherical cells
26
Q

Staphylococcus aureus toxin properties

A
  • very low does
  • resistant to digestive enzymes
  • not destroyed by boiling or canning
  • multiple types exist
27
Q

Staphylococcus aureus growth requirement

A

-Property of s- aureus that is most responsible for its ability to cause food poisoning? - can grow at low aw
-can grow at aw of 0.83
-One of the most resistant non-spore forming human pathogens
Temp: OGT = 35 degree C
–range = 7 to 47.8 degrees C
pH: OGT 7 to 7.5
– range = 4.5 -9.3
-High tolerance of salt and sugars

28
Q

Staphylococcus aureus pathogenesis

A
  • staphylococcal enterotoxin (SE), similar to bacillus cereus
  • single polypeptide
  • Stimulates vegas nerve which causes you to throw up
  • Incubation: 30 min- 6 hours
  • -People get sick very quickly like which bacillus cereus
  • Duration: less than 24 hours
29
Q

Staphylococcus aureus signs and symptoms

A

nausea, vomiting, abdominal cramps.

  • 10% affected individuals seek medical attention
  • severity of illness depends on age and health
30
Q

Staphylococcus aureus reservoirs and foods

A
  • Reservoir: humans
  • Toxic dose: Less than 1 microgram per gram
  • transmission: ingestion of contaminated foods
  • Foods at risk: foods made with hand contact and not cooked afterwards like salad and baked products.
  • Most cases occur in summer and around christmas
    • easter egg hunt, contaminated eggs

Microbiology Lab (9 decks)

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