Exam 3- N251 (foodborne microbiology)

foodborne microbiology

What are major gram-negative foodborne bacteria?

Salmonella, Shigella, E. Coli, Campylobacter

What is the incubation period for Salmonella?

6-48 hour

Ineffective dose for Salmonella?

15-20 cells

When does symptoms show in Shigella?

1-2 days

When does symptoms show in E. Coli?

12hr or 3-10 days

What infection is associated with E. Coli?

Hemolytic Uremic Syndrome (HUS)

Name the most important specie from Campylobacter?

C. jejuni

What shape does campylobacter have?

curved or S-shaped rod

oxygen requirement for campylobacter?

microaerophilic

sensitivity for campylobacter?

oxygen, drying, freezing, salting, acid

what toxin does campylobacter produce?

heat labile toxin

incubation for campylobacter?

2-3 days

ineffective dose for campylobacter?

400-500 cells

complication that can produce campylobacter?

invasive gastroenteritis to become Guillain baren syndrome

can campylobacter survive outside the body?

no, fragile and antibiotic resistant.

What are major foodborne positive?

listeria, staphylococcus, clostridium, bacillus

oxygen requirement for listeria?

facultative anaerobe

Does listeria form endospore?

no production of endospore

species of listeria?

monocytogenes, ivanovii, innocua

incubation period for listeria?

3-70 days

where is listeria most found in?

soil

lab characteristics of listeria?

beta hemolytic (narrow), catalyze positive, oxidase negative, motile 30C

Which specie of listeria is most virulent?

monocytogenes

how many cases in the US of monocytogenes?

1600 illnesses, 250 deaths

disease caused by listeria?

listeriosis

Serious complications due to listeria?

septicemia, meningitis, encephalitis, intrauterine infection, nausea, vomiting,

complication on pregnancy with listeria?

spontaneous abortion

What type of Staphylococcus causes foodborne microorganisms

Staphylococcus Enterotoxin

Are bacteria killed by heat in S. Enterotoxin?

yes

incubation for Staphylococcus enterotoxin?

2-8hr

what is the most common symptom of staph enterotoxin?

vomiting

what are two main species of clostridium?

perfrigens and botulinum

why is foodborne outbreak investigation difficult?

symptoms appear longer after eating contaminated food making hard to identify.

What laboratory technique often used when foodborne organisms are weakened?

enrichment broth

What is a dormant resistant structure that allows bacteria to survive harsh conditions?

spores

general characteristics of clostridium?

gram positive rod, form spores

characteristics of clostridium perfrigens?

rapid generation 6.5min, heat labile, produce subterminal spore

where is it found clostridium perfrigens?

nature

incubation period for perfrigens?

6-24hr

ineffective dose for C. perfrigens?

10th to 8th cell

clostridium botulinum incubation?

12-36hr

What is the disease caused when infants ingest spores that germinated & produced botulinum toxin in the intestine?

infant botulism

describe bacillus cereus?

gram positive, spore forming, facultative anaerobic, rod

foods associated with bacillus cereus?

rice, potatoes, casseroles.

what type of bacillus cereus illness causes?

diarrheal illness and vomiting illness

incubation period for B. Cereus for diarrheal illness?

10-16 hr

incubation for B. Cereus for vomiting illness?

1-6hr

what does MYP agar contain

beef extract and peptone

What is D-Mannitol

Carbohydrate Source

what is the indicator for MYP

Phenol Red is pH indicator

what does egg yolk enrichment provide?

50% lecithin

What does the bacteria fermentation of mannitol produce?

acid products (yellow)

what is B. Cereus on Mannitol Agar

Mannitol negative (pink, red)

what is b. cereus on lacithanase

lacthinase positive (zone precipitate)

norovirus incubation?

12-48 hr

what happened during the salmonella outbreak in the 90’s

liked to schwan’s with ice cream (unpasteurized milk)

what places are exposed to shigella at?

nursing homes and daycare in the 90’s

what is cross contamination?

process where bacteria are unintentionally transfers from one substance to another

what is the pathogenesis of botulism

absorbed toxin from the gut and carried via the blood to the peripheral nerve

what is uninoculated agar on mannitol color

orange