Bacterial Foodborne Diseases Flashcards
bacterial foodborne infections caused by:
intoxication
infection
bacteria associated with intoxication:
Staphylococcus aureus
Bacillus cereus
Clostridium botulinum
Clostridium perfringens
bacteria associated with infection
Campylobacter jejuni Salmonella spp. Escherichia coli Vibrio spp. Listeria monocytogenes
2 ways bacterial toxins are named
by type
by target tissue
endotoxins
gram +
staph, bacillus, clostridium
exotoxins
gram -
campylobacter, salmonella, E. coli, Vibrio
typical symptoms: intoxication
Onset is usually rapid: 30min‐6hrs most commonly, but up to 12 hrs
Illness usually lasts for ~1‐2 days
The primary exception is botulism toxin
(neurotoxin)
typical symptoms: infection
Onset in several hours, to days
Illness usually lasts for several days
Many produce enterotoxins that cause watery diarrhea, ranging from mild to severe
Invasive species, or species with toxins that kill enterocytes, cause dysentery, fever, and possibly septicemia
Staphylococcus aureus: reservoir
skin and nose of many healthy people
Staphylococcus aureus: transmission
Vehicle: food: contaminated with S. aureus
and stored at temperatures favorable to growth and toxin production (danger zone: 40-140 F)
Staphylococcus aureus: clinical signs
Most common foodborne intoxication
rapid onset (30min-6hrs)
Vomiting, diarrhea, cramping
+/- 24hrs
Staphylococcus aureus: prevention
proper food hygiene and storage
Bacillus cereus: reservoir
soil
Bacillus cereus: transmission
Vehicle: food, contaminated with bacteria or
spores and stored at temperatures favorable to growth and toxin production (rice and grains!!)
Bacillus cereus: clinical signs 2 forms
“Enteric Form” Nausea and vomiting
Incubation period 30 minutes to to 6hrs
“Diarrhea form” diarrhea and cramping
Incubation period 8‐16 hrs
Bacillus cereus: prevention
proper food hygiene and storage
Clostridium botulinum: reservoir
Soil; sediments (stream, lake, and coastal waters); intestinal tracts of fish and mammals; gills and viscera of crabs and shellfish; honey
Clostridium botulinum: transmission
Vehicle: food contaminated with spores at
production and then improperly processed
allowing growth and toxin production
Clostridium botulinum: clinical signs (neurotoxin)
flaccid paralysis
small infective dose
onset 18-36hrs
infant botulism (under 1 year)
Clostridium botulinum: prevention
Avoid contamination of food
Don’t feed honey to children less than 12 months of age
Proper preparation of food
Clostridium perfringens: reservoir
Soils, sediments, intestinal tracts of people and animals
Clostridium perfringens: transmission
Vehicle: foods contaminated at production, processing or preparation
Clostridium perfringens: clinical signs
Incubation period 8‐22 hrs
Vomiting, diarrhea, abdominal cramps
Duration 24 hrs
Clostridium perfringens: prevention
proper food processing and preparation
preventing foodborne intoxication
Proper food hygiene
Proper food preparation and storage
Proper canning
Meat hygiene
True/False: Campylobacter jejuni is more prevalent in the summer
true: picnics
Campylobacter jejuni: reservoir
Normal component of intestinal flora of many species
Many bird species
Many mammalian species can be infected
Campylobacter jejuni: transmission
C. jejuni is very fragile
Vehicle is contaminated food, water
Very low infectious dose
Direct contact with farm animals
Campylobacter jejuni: clinical signs
Incubation period: 2‐5 days
Infection and enterotoxin production
Duration of symptoms: 7 days (2‐10 days)
Campylobacter jejuni: prevention
target the vehicle:
– OFFS: reduce infection in birds going to slaughter
– Meat hygiene
– Pasteurization of milk
– Proper handling and cooking of meat esp poultry
Salmonella spp: reservoir
GI flora in many species (birds, cattle, rodents, etc.)
skin flora in reptiles
Salmonella spp: transmission
many foods
Salmonella spp: clinical signs
Incubation period: 12‐72 hours
An invasive type infection
Duration of symptoms: usually 4‐7 days
Salmonella spp: prevention
many strategies
pre-harvest: OFFS
post-harvest: hygiene, pasteurization, cook foods properly, education
Salmonella Enteritidis
Causes egg‐associated salmonellosis
Associated with eating raw or undercooked eggs
E. coli: reservoir
found in many mammalian species
varying pathogenicity
E. coli: transmission
Vehicle: contaminated food
Carcasses contaminated in plant, veggies irrigated with contaminated water, unpasteurized milk, cheese, fruit juices
E. coli: clinical signs (O157H7)
Incubation period: 3‐4 days
Infection + enterotoxin (Shiga toxin) production
Duration of symptoms: 5‐7 days
5-10%: hemolytic uremic syndrome
E. coli: prevention
many different strategies
pre-harvest: OFFS, vaccination
post-harvest: hygiene, pasteurization, cook food properly
true/false: most cases or E. coli are seen from outbreaks
true
Vibrio cholerae: reservoir
People, naturally found in brackish rivers and coastal waters
Vibrio cholerae: transmission
water: most important
transmission: contaminated by water
Vibrio cholerae: clinical signs
Very important world wide
Infection + enterotoxin = VERY watery diarrhea
Vibrio cholerae: prevention
Sanitation, sewage management and water treatment
Food preparation: Proper handling and cooking of food especially shellfish, wash fruits and veggies
Listeria monocytogenes: reservoir
soil, water, animals
Listeria monocytogenes: transmission
vehicle: infected food
replicates at low temperatures (low as 3C)
Listeria monocytogenes: clinical signs
Causes mild food poisoning, or flu‐like symptoms, in most exposed people
– No toxin production
– Septicemia and meningitis
– Abortions
Listeria monocytogenes: prevention
Meat hygiene
Pasteurize milk
Food preparation: Cook food fully, wash fruits and veggies
prevention of foodborne infection
Target the vehicle: no toxins produced in food
- OFFS
- meat hyigene
- pasteurization (capy, salmonella, E. coli, listeria)
- proper handling and cooking of food
- sewage management (Vibro cholera)
