Foodborne and Waterborne Pathogens

Question 1

What is the main cause of foodborne illness?

Answer 1

Intrinsic natural toxins

• Legume toxins
• Algal toxins
• Mycotoxins

Question 2

What are the factors affecting growth of microbes in food?

Answer 2

Nutrients
Antimicrobial barriers
Antimicrobial agents
pH

Question 3

Why do microbes grow well on human food?

Answer 3

Because the nutrients microbes require for survival and growth are the same as those we require

Question 4

What is the main antimicrobial barrier in food?

Answer 4

Skin

• Low water activity
• Low nutrient content
• Resistant to decay

Question 5

What antimicrobial does garlic produce and why?

Answer 5

Allicin

• In response to physical damage
• Limits microbial intrusion

Question 6

What features of food do microbes prefer?

Answer 6

Moist

Neutral pH

Question 7

Why might animal commensal organisms which are harmful to humans accumulate during slaughter?

Answer 7

If removal of internal organs and the guts of animals is not performed correctly or hygienically

Question 8

What are the defences against infection found in the intestinal tract?

Answer 8

Acidic environment
Bile salts
Rapid flow of material
Proteolytic enzymes

Question 9

Why does infectious dose vary between individuals?

Answer 9

Because different host have different health and immunity

Question 10

What microbe causes campylobacteriosis?

Answer 10

Campylobacter jejuni

Question 11

What is campylobacteriosis?

Answer 11

The most common cause of food poisoning

Question 12

What is the major source of campylobacteriosis?

Answer 12

Raw chicken

Question 13

How do campylobacteriosis pathogens cause infection?

Answer 13

Disrupt the membrane of the cells lining the gut so they cannot regulate fluid and chemical balance

Question 14

What is the bodies response to infection by campylobacteriosis?

Answer 14

Inflammation and bleeding in local damaged tissue

Question 15

What microbes cause salmonellosis?

Answer 15

Salmonella species

Question 16

How do salmonellosis pathogens cause infection?

Answer 16

Invade cells in the epithelium of the small intestine and produce toxins

Question 17

In what patients can secondary infection occur as a result of salmonellosis?

Answer 17

Vulnerable patients - those with compromised immune systems

Question 18

What is vero-cytotoxic E.Coli associated with?

Answer 18

Beef or contamination within cattle faeces

Question 19

What are the symptoms of vero-cytotoxic E.Coli?

Answer 19

Toxins produced cause severe stomach cramps, diarrhoea, vomiting and significant bleeding from the gut

Question 20

What microbes cause Listeriosis?

Answer 20

Listeria monocytogenes

Question 21

In what foods is listeriosis common?

Answer 21

Soft cheese
Vacuum packed food
Unwashed vegetables

Question 22

What symptoms does listeriosis cause in healthy people?

Answer 22

Flu like symptoms

Question 23

What symptoms does listeriosis cause in pregnant people?

Answer 23

Abortion
Septicaemia in baby
Meningitis in baby

Question 24

What are the two main preformed toxins in food?

Answer 24

Bacillus cereus

Staphylococcus aureus

Question 25

What does bacillus cereus result from?

Answer 25

Poor food storage

Question 26

What does bacillus cereus do on food?

Answer 26

Germinates and multiplies

Produces heat stable spores which cannot be eliminated by heating

Question 27

What does staphylococcus aureus result from?

Answer 27

Poor hand hygiene

Question 28

What does staphylococcus aureus do on food?

Answer 28

Multiples and produces enterotoxins which are heat stable and result in rapid onset vomiting

Question 29

What types of microbes are foodborne diseases often a result of?

Answer 29

Viruses and fungi

Question 30

Why do protozoa not tend to cause foodborne disease?

Answer 30

They are affected by heat and are therefore eliminated during cooking

Question 31

What are the three entry routes of waterborne disease agents?

Answer 31

Gastrointestinal
Respiratory
Through the skin

Question 32

What microbe is cholera caused by?

Answer 32

Vibrio cholerae

Question 33

What are the symptoms of cholera?

Answer 33

Diarrhoea
Severe dehydration
Potentially death

Question 34

How do cholera pathogens cause infection?

Answer 34

Act on mucosal epithelium of the digestive tract

Prevent regulation of sodium and chloride resulting in massive loss of water from cells

Question 35

What microbe causes cryptosporidiosis?

Answer 35

Cryptosporidium parvum = protozoa

Question 36

What are the symptoms of cryptosporidiosis?

Answer 36

Abdominal pain
Diarrhoea
Weight loss
Apetite loss

Question 37

Why does cryptosporidiosis cause disease through water and not food?

Answer 37

Water = oocysts are resistant to chlorine and disinfectants 
Food = killed by heating

Question 38

What microbe is legionnaires disease caused by?

Answer 38

Legionella pneumophila

Question 39

What are the sources of legionnaires diseases?

Answer 39

Inhaling contaminated air

On shower heads

Question 40

What are the symptoms of legionnaires disease?

Answer 40

Severe pneumonia

Question 41

What group of people are more at risk from legionnaires disease?

Answer 41

Elderly

Question 42

What microbe causes leptospirosis?

Answer 42

Leptospira interrogans

Question 43

How do leptospirosis bacteria enter the body?

Answer 43

Through breaks in the skin

Question 44

What are the symptoms of leptospirosis?

Answer 44

Influenza like illness

Question 45

What complications can leptospirosis cause?

Answer 45

Jaundice 
Hepatitis 
Kidney damage 
Damaged blood vessels
Meningitis