Salmonella Transmission: Foodborne, Person-to-Person & Environmental Routes

Salmonella (non-typhoidal serovars: Enteritidis, Typhimurium) causes ~1.35M US illnesses annually.

Transmission Routes

1. Foodborne (95%):
   • Animal products: Eggs, poultry, beef, pork, raw milk.
   • Produce: Contaminated irrigation water, manure, handling (sprouts, melons, tomatoes, leafy greens).
   • Processed: Peanut butter, flour, spices, frozen meals.
2. Animal Contact:
   • Reptiles/amphibians (turtles, lizards) – high shedding.
   • Poultry (backyard flocks), livestock, petting zoos.
   • Pet food/treats (raw diets, pig ears).
3. Person-to-Person (Fecal-Oral):
   • Inadequate hand hygiene after toileting/diaper changing.
   • Sexual practices (oral-anal).
   • Outbreaks in daycares, nursing homes.
4. Environmental/Fomite: Contaminated surfaces, utensils, water.

Risk Factors for Severe Disease

• Age <5, >65.
• Immunocompromise (HIV, chemo, steroids, transplant).
• Hemoglobinopathies (S. Typhimurium → bacteremia).
• Antacid/PPI use (↓ gastric acid barrier).

Prevention

• Cook to safe temps (poultry 165°F, eggs firm).
• Separate raw/ready-to-eat; prevent cross-contamination.
• Wash hands, produce, surfaces.
• No raw milk, raw eggs, raw dough.
• Reptile pets: High-risk households avoid.