Lecture 13: Food Poisoning Flashcards Preview

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Flashcards in Lecture 13: Food Poisoning Deck (75):
1

List food hazards in order of concern by regulatory agencies (FDA, CDC)

1. Microbial
2. Nutritional
3. Environmental
4. Natural toxicants
5. Pesticide residues
6. Food additives

2

Which microorganisms can only multiple in food?

Yeasts and molds

3

Which microorganism can multiply in food and humans?

Bacteria

4

Which microorganism can only multiply in humans?

Human viruses

5

Which microorganism multiplies in bacteria?

Bacterial viruses

6

Name the 2 general types of food-borne illness

Intoxications and infections

7

Food-borne intoxication

-aka food poisoning
-Relatively acute illness associated with the consumption of PRE-FORMED microbial toxins in food
-Microorganism must grow in the food, but not necessarily in consumer

8

Under the best conditions, a bacterial cell can divide every ____?

20-30 mins

9

Name the 3 food-borne intoxications we learned about in class

-Staphylococcus aureus
-Clostridium botulinum
-Bacillus cereus

10

How does one get staphylococcal intoxication?

Ingestion of a pre-formed enterotoxin (stomach toxin) from a Staphyloccocus species

11

What are the symptoms of staphylococcal intoxication?

-Salivation
-Nausea & vomitting
-Retching
-Abdominal cramps
-Diarrhea

12

Staphylococcal etiology: What makes it a problem?

-Ubiquitous in the environment
-Can grow in nasal and pharyngeal area of humans
-In CA, 50% of humans are carriers

13

Manifestations of staphylococcal intoxication

-Sudden onset = 1-6 hrs
-Short duration = 2-24 hrs
-Usually attributed to other causes (one-day flu)
-Fatalities are rare

14

What are the conditions under which staphylococcal toxin are produced?

-50-140 F
-Rapid growth at 70-105 F
-Aerobic conditions (desires oxygen to grow)

15

What kinds of foods are high incidence for staphylococcal poisonings?

-Custard-filled bakery products
-Sliced cooked meats
-Chicken calad
-Cheeses
-Sausages
-Spray-dried milk

16

Staphylococcal prevention

-Low temp storage for foods
-Pasteurization followed by preventing contamination

17

What is the botulinum toxin resistant to?

Proteolytic enzymes in GI tract

18

What is Clostridium botulinum?

-Gram-positive (thick-walled), anaerobic, spore-forming bacterium
-Ubiquitous in soil

19

What is the causal agent of botulism?

A neurotoxin, heat-labile protein

20

Symptoms of botulism

-Nausea & vomitting = 12-24 hrs
-Weakness, double vision, lack of energy
-Death in 2-9 days from respiratory paralysis

21

Infant botulism

-C. botulinum can colonize infants' (< 1 yr old) colon
-Spores present in honey and corn syrup
-"Floppy baby" syndrome may be responsible for some SIDS cases
-Symptoms = constipation, no facial expression, poor feeing, weak cry, reduced movement, drooling

22

Prerequisites for botulism toxicity

-Obligate anaerobe
-Water activity > 0.9 (water must be available)
-pH > 4.6 (low acid food)

23

What are 3 reasons to add nitrite to meats?

-Taste
-To fix color (pink of sausage)
-Inhibit growth of C. botulinum

24

Are nitrites carcinogens?

-Nitrites can make nitrosamines, which are carcinogens at high levels
-Food scientists can keep these levels very low

25

Botulism prevention

-Heat processing according to National Food Processors Association (NFPA)
-Refrigeration < 40 F
-Hygienic food handling, especially if pH > 4.6
-Heat food to boiling temp for 10 mins

26

How is home canned food a major source of botulism?

Insufficient processing of low acid foods such as green beans, veggies, fish, meats

27

What are Bacillus?

Aerobic, rod shaped, gram positive, spore-forming bacteria

28

Where does Bacillus cereus live?

In cereals and meat

29

What 2 toxins does B. cereus make? What are the symptoms associated with them?

-Small peptide = heat stable; vomitting 1/2-6 hrs after meal
-Large protein = heat labile; diarrhea 6-15 hrs after meal

30

What is the symptom of B. cereus in meat, milk, veggies, fish?

Diarrhea

31

What is the symptom of B. cereus associated with rice and some other starchy foods?

Vomitting

32

Food-borne infections

-Food is the vector that carries high levels of the pathogen to the body
-Illness caused by pathogen colonizing or invading the body

33

What bacterium causes Salmonellosis?

Salmonella enterica

34

What are the symptoms of Salmonella?

-Gastroenteritis
-Fever (typhoid)
-Diarrhea
-Cramping

35

How is salmonella transmitted?

By the fecal-oral route (food contaminated with feces)

36

Salmonellosis prevention

-Hygienic food handling
-High temps for cooking food
-Rigid temp control and hygienic practices for processed foods

37

In the U.S., what bacterium is the second leading killer due to food borne illness?

Listeria monocytogenes

38

What does listeria monocytogenes cause?

Meningitis (infection of the brain)

39

How is listeria monocytogenes particularly harmful to pregnant women?

This bacteria can cross the placental barrier to cause a fatal infection of the developing fetus

40

What is the USDA's policy on listeria monocytogenes?

Zero tolerance

41

How fatal is listeria monocytogenes?

~25% fatal in susceptible individuals (pregnant women, very old, very young, those on immunosuppressant therapy, HIV)

42

Under what conditions does listeria monocytogenes thrive?

-High osmotic strength (deli meats)
-Temp < 7 C (45 F)
-Cross-contamination followed by refrigeration

43

In what foods is listeria monocytogenes most common?

-Low-acid cheeses
-Cured and raw meat products

44

What symptom does E. coli cause?

Dysentery (bloody diarrhea)

45

What foods is E. coli most common in?

Rare hamburgers, unwashed produce

46

What parasite causes trichinellosis?

Trichinella spiralis (trichina worm)

47

What foods can cause trichinellosis?

From undercooked pork, bear, dog, cat

48

How common is trichinellosis?

Rare in the U.S.

49

How can trichinellosis be prevented?

Freezing food for 3 weeks

50

What parasite causes anisakiasis?

Anisakis simplex (roundworm)

51

What food causes anisakiasis?

Undercooked fish (sushi)

52

How can you prevent anisakiasis?

Freeze food at -20 C for 24 hrs

53

What are the smallest pathogens?

Viruses

54

Where do viruses grow?

In the body, not food

55

How are viruses transmitted?

Through improper food handling

56

How do viruses multiply?

Hijack the host's genetic & protein synthesis apparatus --> force it to make more viruses

57

Are viruses alive?

Not really
-No metabolism, no energy source, no metabolic waste

58

Why don't antibiotics work on viruses?

Antibiotics interfere with microbial cell wall synthesis, protein synthesis --> viruses don't have these

59

What is the common route for viruses?

Fecal to oral route

60

What does it mean that a virus is an obligate parasite?

No life without a host

61

How do infected people "shed" virus particles?

In feces

62

What is Hepatitis A?

Disease due to viral infection of the liver

63

Symptoms of Hepatitis A

Sudden fever, malaise, nausea, anorexia, abdominal discomfort, jaundice

64

What happens if Hepatitis A is left untreated?

Irreversible liver damage that can lead to death

65

How is Hepatitis A transmitted?

-Person-to-person contact through fecal contamination
-Any food handled by people (salads, shellfish)

66

What is another name for Norovirus?

Cruise Ship Virus

67

Symptoms of Hepatitis A

Sudden fever, malaise, nausea, anorexia, abdominal discomfort, jaundice

68

What happens if Hepatitis A is left untreated?

Irreversible liver damage that can lead to death

69

How is Hepatitis A transmitted?

-Person-to-person contact through fecal contamination
-Any food handled by people (salads, shellfish)

70

HACCP

Hazard Analysis & Critical Control Points
-Systematic approach to food safety
-Identifies factors where lack of control could potentially result in an unacceptable health risk

71

How is Norovisus transmitted?

Fecal-oral route

72

What is considered an infectious dose for Norovirus?

18 virus particles

73

In what foods is Norovirus most common?

-Water
-Raw or under-steamed shellfish
-Any foods handled by infected individuals

74

HACCP

Hazard Analysis and Critical Control Points

75

Two most important sanitation protocols

-Wash your hands
-Avoid cross contamination carried on cutting boards, knives, sponges, and hands