Bacterial Food Poisoning

Question 1

What is the definition of foodborne illness?

Answer 1

Disease caused by consumption of food contaminated with poisoning agents including chemicals or infectious agents like viruses, parasites, bacteria or their toxins.

Question 2

According to the WHO in 2010, how many people were affected by foodborne diseases?

Answer 2

600 million people.

Question 3

How many deaths were caused by foodborne diseases according to the WHO in 2010?

Answer 3

420,000 deaths.

Question 4

What percentage of foodborne diseases are produced by pathogenic bacteria?

Answer 4

60-90%.

Question 5

What are the two main types of food-related disease?

Answer 5

• Food-borne infection
• Food-intoxication

Question 6

What is the main manifestation of bacterial food poisoning?

Answer 6

Gastroenteritis.

Question 7

What is the difference between food-borne infection and food intoxication?

Answer 7

• Food-borne infection: Organisms colonize the GI tract and grow before producing toxins or invading tissue.
• Food intoxication: Toxin is ingested without the need for living organisms.

Question 8

Define exotoxin.

Answer 8

A toxin that is secreted by microorganisms into the surrounding medium.

Question 9

Define endotoxin.

Answer 9

A toxin that is confined inside the microorganisms and is released only when the microorganisms are broken down or die.

Question 10

What are enterotoxins?

Answer 10

Toxins which adversely affect the gut.

Question 11

What are common symptoms of Campylobacter gastroenteritis?

Answer 11

• Fever
• Stomach cramps
• Watery diarrhoea
• Rarely vomiting

Question 12

What is the principal source of Salmonella enteritidis infections?

Answer 12

Hen eggs.

Question 13

What are the main types of foodborne illness caused by Salmonella?

Answer 13

• Enterocolitis
• Enteric fever (typhoid)
• Bacteraemia
• Systemic disease

Question 14

What factors contribute to the virulence of Salmonella spp.?

Answer 14

Ability to translocate across the gut barrier and replicate within macrophages.

Question 15

What is the physiological pH range for the growth of Salmonella spp.?

Answer 15

4.5 to 9.5 (optimum pH 6-7.5).

Question 16

What is the mortality rate for listeric meningitis?

Answer 16

Up to 70%.

Question 17

What are the two types of listeriosis?

Answer 17

• Non-invasive listeriosis
• Invasive listeriosis

Question 18

Fill in the blank: The faecal-oral route is key in the spread of _______.

Answer 18

foodborne diseases.

Question 19

True or False: Campylobacter jejuni is the most common bacterial cause of foodborne illness in the developed world.

Answer 19

True.

Question 20

What is the treatment for Campylobacter gastroenteritis?

Answer 20

Supportive therapy, fluid and electrolyte replacement.

Question 21

What is the significance of the biphasic flagella in Campylobacter jejuni?

Answer 21

It is crucial for the initial interaction with the host and facilitates colonization of the intestine.

Question 22

What is the role of the Food Standards Agency (FSA) regarding Campylobacter spp. in chickens?

Answer 22

To measure efforts to reduce the levels of Campylobacter spp. in chickens.

Question 23

How can Salmonella be diagnosed in stool samples?

Answer 23

Laboratory tests that identify Salmonella in the stool.

Question 24

What is the economic burden of Campylobacter gastroenteritis compared to its medical burden?

Answer 24

The burden is economic rather than medical.

Question 25

What is the main reservoir for Campylobacter jejuni?

Answer 25

Animals, particularly birds, dogs, cats, and raw uncooked poultry.

Question 26

List the common sources of Listeria monocytogenes outbreaks.

Answer 26

* Contaminated milk * Soft cheeses * Vegetables * Meat

Question 27

Fill in the blank: The primary route of transmission for Salmonella is through _______.

Answer 27

contaminated food or water.

Question 28

What is the treatment for non-typhoid Salmonella illness?

Answer 28

Supportive therapy such as fluid and electrolytes.

Question 29

What type of organism is Listeria monocytogenes?

Answer 29

Gram positive rod ## Footnote It is a facultative anaerobe, catalase-positive, and motile.

Question 30

What is the mortality rate of septicemia caused by Listeria monocytogenes?

Answer 30

50% mortality ## Footnote Perinatal/neonatal infections have a mortality rate greater than 80%.

Question 31

What is a proposed food additive to control Listeria monocytogenes?

Answer 31

Listeria phage P100

Question 32

What are the characteristics of Listeria monocytogenes?

Answer 32

* Gram positive rod * Motile by flagella at lower temperatures * Capable of growth at a wide range of temperatures (4 to 40°C) * Found widely in soil, water, and intestinal tracts

Question 33

How is listeriosis acquired?

Answer 33

From contaminated food

Question 34

What are the symptoms of Clostridium perfringens food poisoning?

Answer 34

* Diarrhea * Severe abdominal pain * Usually no fever

Question 35

What is the incubation period for symptoms to develop after consuming contaminated food with Clostridium perfringens?

Answer 35

8 to 16 hours

Question 36

What does Nagler's reaction help determine?

Answer 36

The number of bacteria in the feces

Question 37

What is the primary method to prevent the growth of Clostridium perfringens spores?

Answer 37

Cooking food thoroughly to recommended temperatures

Question 38

What is the most acutely toxic substance known to humans?

Answer 38

Botulinum neurotoxin (BoNT)

Question 39

What are the symptoms of botulism?

Answer 39

* Nausea * Vomiting * Fatigue * Dizziness * Headache * Gut pains * Muscle paralysis * Double vision * Respiratory failure

Question 40

What environmental conditions are optimal for the formation of BoNT?

Answer 40

* High humidity * pH exceeding 4.6 * Anaerobic conditions

Question 41

What is the mechanism of action of botulinum neurotoxin?

Answer 41

Prevents neurotransmitter release at the neuromuscular junction

Question 42

What is a common method for detecting C. botulinum?

Answer 42

Enzyme-linked immunosorbent assay (ELISA)

Question 43

What should be administered if botulism is diagnosed early?

Answer 43

Antitoxin

Question 44

What is the primary reservoir for E. coli O157:H7?

Answer 44

Cattle

Question 45

What are the typical features of E. coli O157 gastroenteritis?

Answer 45

* Abdominal pain * Non-bloody diarrhea becoming bloody after 1-4 days * No fever

Question 46

What toxins are produced by E. coli O157?

Answer 46

* Shiga-like toxins Stx1 and Stx2

Question 47

What is the incubation period for Bacillus cereus emetic syndrome?

Answer 47

0.5 to 6 hours

Question 48

What type of toxin is associated with Bacillus cereus diarrheal syndrome?

Answer 48

Protein enterotoxins

Question 49

What are the symptoms of Bacillus cereus emetic syndrome?

Answer 49

* Nausea * Vomiting * Malaise

Question 50

What food products are commonly implicated in Bacillus cereus illness?

Answer 50

* Meat products * Soups * Veg * Milk and milk products * Fried and cooked rice * Pasta * Pastry * Noodles

Question 51

What are common symptoms of Bacillus cereus infection?

Answer 51

Nausea, vomiting, malaise ## Footnote These symptoms may arise from foodborne illness caused by Bacillus cereus.

Question 52

What types of food are commonly implicated in Bacillus cereus outbreaks?

Answer 52

* Meat products * Soups * Vegetables * Milk and milk products * Fried and cooked rice * Pasta * Pastry * Noodles ## Footnote These foods can harbor Bacillus cereus and lead to foodborne illness.

Question 53

What methods can be used to detect Bacillus cereus?

Answer 53

* Differential media methods * ELISA for diarrheal toxin production * PCR methods for bacteria and toxins ## Footnote These methods help identify Bacillus cereus in food samples.

Question 54

What is the heat resistance of Bacillus cereus spores affected by?

Answer 54

High salt concentrations and gradual heating ## Footnote Spores lose heat resistance in acidic environments.

Question 55

What key event occurred in May/June 2014 related to Bacillus cereus?

Answer 55

Outbreak linked to intravenous liquid (TPN) in England, resulting in 23 cases and 3 deaths ## Footnote This outbreak was traced back to a specific sterile area at ITH Pharma.

Question 56

What was recalled by Mars in August 2014?

Answer 56

Chocolate and milk drink products due to elevated levels of Bacillus species ## Footnote This was part of food safety measures in response to contamination.

Question 57

What are the two different toxins produced by Bacillus cereus?

Answer 57

* Emetic toxin * Diarrheal toxin ## Footnote These toxins are responsible for the different foodborne syndromes caused by Bacillus cereus.

Question 58

What type of bacteria is Staphylococcus aureus?

Answer 58

Non-motile, non-spore forming cocci ## Footnote Staphylococcus aureus is commonly associated with foodborne illnesses.

Question 59

What are the common symptoms of Staphylococcus aureus food poisoning?

Answer 59

* Nausea * Vomiting * Abdominal cramps * Diarrhea ## Footnote Symptoms typically develop within 30 minutes to 7 hours after consuming contaminated food.

Question 60

What is the optimal growth temperature range for Staphylococcus aureus?

Answer 60

7-48°C ## Footnote This range allows for rapid growth of the bacteria in food.

Question 61

What are the common foods implicated in S. aureus food poisoning?

Answer 61

* Various ready-made foods * Meat and poultry products * Potato salad * Shellfish * Sandwiches * Ready-to-eat vegetable salads (improperly stored) ## Footnote Contaminated food storage and handling can lead to outbreaks.

Question 62

True or False: Staphylococcal enterotoxins are heat stable.

Answer 62

True ## Footnote The enterotoxins produced by Staphylococcus aureus resist heat treatment.

Question 63

What is the treatment for Staphylococcus aureus food poisoning?

Answer 63

* Rehydration * Anti-emetics ## Footnote Antibiotics are ineffective against this type of food poisoning.

Question 64

Fill in the blank: Bacillus cereus is especially problematic in the _______ industry.

Answer 64

dairy ## Footnote This is due to its ability to survive in dairy products and cause spoilage.

Question 65

What outbreak was traced to lasagne in 1984?

Answer 65

Outbreak of Staphylococcus food poisoning in a family in Italy ## Footnote The outbreak was linked to pasta contaminated with S. aureus.