CPFS Foodborne Illness & Pathogens 1 — Questions and Answers
Question 1: What temperature range is known as the 'danger zone' in which foodborne pathogens grow most rapidly?
- 0°F to 32°F
- 41°F to 135°F (Correct answer)
- 140°F to 165°F
- 32°F to 70°F
Correct answer: 41°F to 135°F
The danger zone is 41°F to 135°F (5°C to 57°C), where most pathogens multiply rapidly and food should not be held for more than 4 hours total.
Question 2: Which pathogen is most commonly associated with undercooked poultry and is the leading cause of bacterial foodborne illness in the United States?
- Salmonella spp.
- Campylobacter jejuni (Correct answer)
- Listeria monocytogenes
- Clostridium perfringens
Correct answer: Campylobacter jejuni
Campylobacter jejuni is the most frequently reported bacterial cause of foodborne illness in the US and is strongly linked to undercooked poultry and raw milk.
Question 3: Which characteristic of the toxin produced by Staphylococcus aureus makes it especially dangerous in foodservice?
- It is destroyed at refrigeration temperatures
- It requires live bacteria to cause illness
- It is heat-stable and survives cooking temperatures (Correct answer)
- It only forms in acidic foods
Correct answer: It is heat-stable and survives cooking temperatures
Staphylococcal enterotoxin is heat-stable and can survive temperatures that kill the bacteria, meaning reheating contaminated food will not eliminate the toxin.
Question 4: Hepatitis A virus outbreaks in foodservice are most often traced to which source?
- Contaminated equipment surfaces
- An infected food handler with poor personal hygiene (Correct answer)
- Improperly refrigerated dairy products
- Undercooked ground beef
Correct answer: An infected food handler with poor personal hygiene
Hepatitis A is primarily spread via the fecal-oral route, and infected food handlers who do not wash hands properly after using the restroom are the most common source in foodservice outbreaks.
Question 5: Which foodborne pathogen is responsible for producing a preformed toxin that causes illness within 1–6 hours after ingestion?
- Clostridium botulinum
- Salmonella Typhi
- Staphylococcus aureus (Correct answer)
- Norovirus
Correct answer: Staphylococcus aureus
Staphylococcus aureus produces a preformed enterotoxin in food, resulting in rapid symptom onset (typically 1–6 hours) including nausea, vomiting, and stomach cramps.
Question 6: Which condition is most likely to promote the growth of Clostridium perfringens in a foodservice setting?
- Rapidly cooling large batches of cooked meat in deep pots (Correct answer)
- Storing raw poultry on the bottom shelf of the walk-in cooler
- Holding cooked beans at 45°F
- Using chlorinated water to wash produce
Correct answer: Rapidly cooling large batches of cooked meat in deep pots
Clostridium perfringens thrives when large volumes of cooked meat cool too slowly, passing through the danger zone for extended periods and allowing spores to germinate and multiply.
Question 7: E. coli O157:H7 is classified as a particularly dangerous pathogen in foodservice because it produces which harmful substance?
- Aflatoxin
- Shiga toxin (Correct answer)
- Botulinum toxin
- Mycotoxin
Correct answer: Shiga toxin
E. coli O157:H7 produces Shiga toxin (Stx), which can cause severe hemorrhagic colitis and hemolytic uremic syndrome (HUS), especially in young children and the elderly.
CPFS Foodborne Illness & Pathogens 1
What temperature range is known as the 'danger zone' in which foodborne pathogens grow most rapidly?