Food Poisoning: Causes, Symptoms, Treatment, and Prevention

Foodborne illness (food poisoning) results from consuming food contaminated with pathogens (bacteria, viruses, parasites) or their toxins. CDC estimates 48 million cases annually in the U.S.

Common Pathogens and Sources

• Bacteria: Salmonella (eggs, poultry, produce), Campylobacter (poultry, raw milk), E. coli O157:H7 (undercooked beef, sprouts), Clostridium perfringens (reheated meats), Staph aureus (toxin in cream pies, meats left out), Listeria (deli meats, soft cheese — high risk in pregnancy).
• Viruses: Norovirus (leading cause; person-to-person, contaminated food/water), Hepatitis A.
• Parasites: Giardia, Cryptosporidium, Cyclospora (contaminated produce/water).

Symptoms (Onset Hours to Days)

• Nausea, vomiting, diarrhea (watery or bloody)
• Abdominal cramps, fever, headache, myalgia, fatigue
• Dehydration signs: dry mouth, reduced urine, dizziness

When to Seek Care

• Bloody diarrhea, high fever (>38.5°C / 101.3°F)
• Signs of severe dehydration
• Symptoms >3 days, or in high-risk groups (pregnant, <5 yrs, >65 yrs, immunocompromised)
• Neurologic symptoms (blurred vision, weakness — botulism)

Prevention (Four Core Practices)

1. Clean: Wash hands, surfaces, produce.
2. Separate: Raw meat/poultry/seafood from ready-to-eat foods.
3. Cook: Safe internal temperatures (165°F poultry, 160°F ground meat, 145°F whole cuts + rest).
4. Chill: Refrigerate ≤40°F (4°C) within 2 hours (1 hour if >90°F/32°C). Thaw safely (fridge, cold water, microwave).