Foodborne Pathogens - Bacteria Flashcards
What is the epidemiological triad?
- Agents
- Hosts
- Environment
And how these three interact.
Why is epidemiology important in food microbiology?
- ## helps us to understand the occurrence of foodborne illnesses which are constantly changing
When it comes to infections, what are some things to consider?
- The chain of infection
- Type of illness caused
- The incubation period
- Host
- Associated Food Vehicles
Discuss foodborne illness surveillance.
- This is the systematic collection of data with analysis and dissemination of results
- The surveillance used can be passive or active, national or regional
What is the purpose of this surveillance?
- Identification, control and prevention of foodborne outbreaks
- used to determine the causes of said outbreaks
- Monitoring purposes
- Quantify and reduce the burden of foodborne illness
How are risk factors and food hazards determined using foodborne illness surveillance?
- Population Surveillance
- Surveillance for food hazards
- Environmental monitoring
- Finished-product testing
- Behavioral risk factor surveillance
6 Environmental hazard surveillance
What are the 3 types of foodborne diseases?
- Foodborne infection
- Foodborne intoxication or poisoning
- Foodborne toxico-infection
Define each type of foodborne disease and provide examples of the bacteria associated with each type.
- Foodborne infection - eating food containing living harmful microorganisms
Eg. Salmonella, Listeria monocytogenes, Campylobacter jejuni, Yersinia enterocolitica - Foodborne intoxication or poisoning - eating food containing toxins produced by microorganisms that may no longer be present
Eg. Staphylococcus aureus, Bacillus cereus, Clostridium botulium - Foodborne Toxico-infections - eating food containing large amount of non-invasive pathogens that cause illness by producing toxins
Eg. Clostridium perfringens, Bacillus cereus, Shigella and E.coli o157:h7
What is the difference between exotoxins and enterotoxins?
Exotoxins are secreted out of the bacterial cell while endotoxins are toxins that are stored within the bacteria once the bacteria remains alive.
What are some of the ways food can become contaminated?
- Not washing hands before cooking
- Not fully cooking contaminated foods
- Improper thawing
- Improper cooling
- Not properly cleaned preparation surfaces
- Storing foods in the danger zone
What is the danger zone temp?
Between 40 degrees F (4 degrees C) and 140 degrees F (60 degrees C)
List the bacterial agents of foodborne disease.
- Salmonella
- Shigella spp
- Pathogenic E. coli
- E. coli O157:H7
- Campylobacter
-Yersinia - Listeria monocytogenes
- Clostridium botulinum
- Bacillus cereus
- Staphylococcus aureus
What are enteric bacteria?
Bacteria that exist in the gut of animals and humans
List the enteric pathogens.
Salmonella, Shigella, Campylobacter, Yersinia, Escherichia, Vibrio and Listeria
List the Viral Agents of Foodborne diseases.
- Hepatitis
- Norovirus
- Astrovirus
- Rotovirus
List Parasitic Agents of foodborne disease.
- Giardia
- Cyclospora
- Cryptosporidium
- Toxoplasma
- Trichnella
What are the categories for detecting pathogens?
- Collection
- Pheotypic & Molecular Detection
- Typing
- Detection & Typing Future Prospects
What are some examples of the detection of pathogen methods?
- Collection: Fresh stool specimen, Rectal Swab, Transport Medium (Buffered Glycerol Saline (BGS) medium)
- Phenotypic & Molecular: Selective media, PCR, Biochemical assays
- Typing: Dipsticks, Pulse field gel electrophoresis (PFGE), Microarrays
- Future Prospects: Sequencing, MLST
What species of Campylobacter causes foodborne and zoonotic illnesses?
- C. jejuni
- C. coli
- C. lari
-C. upsaliensis
What kinds of food are Campylobacter found in?
unpasteurized milk and dairy products, raw meat/poultry, domestic pets,
and non-chlorinated or faecal-contaminated water
Where is the primary habitat of Salmonella?
- the intestinal tract of birds, reptiles, farm animals, humans and insects.
- Organisms shed in faecal material.
- Asymptomatic carriers may routinely shed organisms contaminating
food and water.
List the sources of contamination for Salmonella.
- water
- soil
- insects
- domestic and wild animals
- human intestinal tract
Foods associated with salmonella include:
- High protein foods (meat, poultry, fish, milk)
- Egg and egg products (cake mixes, cookie dough, custards, sauces and
creams) - commercially prepared and packed foods
- Raw produce contaminated by faecal matter
Name the salmonella species found in humans only.
- S. Typhi (typhoid fever)
- S. Paratyphi A and C (paratyphoid fever)
Name the host-adapted salmonella serovars.
S. gallinarum (Poultry)
S. dublin (cattle)
When and where did the largest salmonella outbreak occur?
- Salmonella enteriditis
occurred in 1994 - 224,000 persons in 41 US states
- Linked to ice cream produced from milk transported in tanker trucks that
previously hauled eggs
When and where was the third largest salmonella outbreak?
- S. typhimurium
occurred in 1974 on Navajo Indian Reservation - 3400 persons affected out of 11, 000
- Linked to potato salad improperly stored after preparation 16 hours prior to
serving
What are the 5 classes of Pathogenic E. coli?
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Enterotoxigenic
ETEC
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Enteroinvasive
EIEC
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Enteropathogenic
EPEC
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Enteroaggregative
EAggEC
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Enterohaemorrhagic
EHEC
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Diffusely
Adherent
DAEC
