Key Takeaways
- Big Six require exclusion: Norovirus, Hepatitis A, Salmonella Typhi, Nontyphoidal Salmonella, Shigella, E. coli (STEC)
- Norovirus is the #1 cause of foodborne illness outbreaks in the US
- Listeria can grow at refrigerator temperatures
- Staph aureus toxin is NOT destroyed by cooking
- Four key practices: Clean, Separate, Cook, Chill
Last updated: January 2026
7.2 Common Foodborne Pathogens
Understanding the major pathogens, their sources, and symptoms helps prevent outbreaks.
The Big Six Pathogens
These six pathogens are highly contagious and require infected food handlers to be excluded from work:
| Pathogen | Sources | Symptoms | Prevention |
|---|---|---|---|
| Norovirus | Shellfish, ready-to-eat foods, infected handlers | Vomiting, diarrhea, nausea (24-48 hrs) | Handwashing, exclude sick workers |
| Hepatitis A | Shellfish, ready-to-eat foods, contaminated water | Fever, jaundice, fatigue (15-50 days) | Handwashing, cook shellfish properly |
| Salmonella Typhi | Ready-to-eat foods, beverages | Typhoid fever, high fever, weakness | Handwashing, exclude carriers |
| Nontyphoidal Salmonella | Poultry, eggs, dairy, produce | Diarrhea, fever, cramps (12-72 hrs) | Cook to proper temp, prevent cross-contamination |
| Shigella spp. | Ready-to-eat foods, contaminated water | Bloody diarrhea, fever, cramps | Handwashing, exclude sick workers |
| E. coli (STEC) | Undercooked beef, raw produce, unpasteurized juice | Severe cramps, bloody diarrhea (3-4 days) | Cook ground beef to 155°F, wash produce |
Other Important Pathogens
| Pathogen | Sources | Key Points |
|---|---|---|
| Listeria monocytogenes | Deli meats, soft cheese, raw sprouts | Grows in refrigerator temps; dangerous to pregnant women |
| Clostridium botulinum | Improperly canned foods, garlic-in-oil | Produces deadly toxin; causes paralysis |
| Clostridium perfringens | Cooked meat and poultry | "Cafeteria germ" - from improper cooling |
| Staphylococcus aureus | Foods touched by hands (salads, cream pastries) | Toxin not destroyed by cooking |
| Bacillus cereus | Rice, pasta, potatoes | Two forms: vomiting or diarrhea |
| Campylobacter | Raw/undercooked poultry, unpasteurized milk | Most common bacterial cause of diarrhea |
Viruses vs. Bacteria
| Characteristic | Viruses | Bacteria |
|---|---|---|
| Can multiply in food | No | Yes |
| Require host to reproduce | Yes | No |
| Destroyed by cooking | Usually | Usually |
| Prevented by | Handwashing, excluding sick workers | Temperature control, cooking, sanitation |
Key Insight: Norovirus is the #1 cause of foodborne illness outbreaks in the US. It spreads easily from person to person and through contaminated food.
Preventing Foodborne Illness
The Four Key Practices:
- Clean - Wash hands and surfaces often
- Separate - Don't cross-contaminate
- Cook - To proper internal temperatures
- Chill - Refrigerate promptly (within 2 hours, or 1 hour if above 90°F)
Test Your Knowledge
Which pathogen is the #1 cause of foodborne illness outbreaks in the US?
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Test Your Knowledge
Which pathogen can grow at refrigerator temperatures?
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Test Your Knowledge
What food is MOST commonly associated with Salmonella?
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Test Your Knowledge
What are the four key practices for preventing foodborne illness?
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Test Your Knowledge
Which pathogen produces a toxin that is NOT destroyed by cooking?
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