Understanding what causes salmonella

Salmonella is more than just a news headline—it’s one of the leading causes of foodborne illness in the United States.

While most cases result in uncomfortable but short-lived symptoms, salmonella infections can have serious—and even fatal—consequences, especially for children, the elderly, and immunocompromised individuals. For food businesses, the stakes are equally high: a single outbreak can spark costly recalls, lawsuits, and long-term brand damage.

Where does salmonella come from?

Salmonella naturally lives in the intestines of humans and animals. The bacteria are shed through feces and can contaminate food, water, surfaces, and even processing equipment.

Here’s where contamination often begins:

Livestock and poultry farms: Salmonella is commonly found in the digestive tracts of chickens, cows, pigs, and other animals.
Slaughter and processing facilities: Improper sanitation, cross-contamination, or temperature abuse during processing can allow the bacteria to spread.
Field contamination: Runoff from nearby animal operations can contaminate irrigation water used on crops like leafy greens and tomatoes.
Poor hygiene and handling: Food handlers who don’t follow hygiene protocols can unintentionally spread salmonella to ready-to-eat foods.

The many sources of salmonella in food

Contrary to popular belief, salmonella doesn’t just show up in undercooked chicken or raw eggs. Outbreaks have been traced to a surprisingly wide range of foods, including:

Poultry and eggs
Unpasteurized milk or juice
Raw or undercooked meat
Fresh produce (e.g. cucumbers, cantaloupes, leafy greens)
Processed foods like peanut butter, flour, frozen meals, and powdered milk
Spices and seasonings, often imported without adequate testing

Contamination can happen at virtually any point along the supply chain, from farm to fork.

How salmonella spreads

The most common route of infection is by eating contaminated food or drinking contaminated water. However, salmonella can also spread via:

Contact with infected animals, especially reptiles, amphibians, and backyard poultry
Touching contaminated surfaces and then touching your mouth or food
Person-to-person contact in places with poor hand hygiene (e.g. daycares, care homes)

Once ingested, salmonella travels to the intestines, where it causes a variety of symptoms, typically within 6 hours to 6 days after exposure.

What are the symptoms of salmonella infection?

Most people infected with salmonella experience:

Diarrhea (sometimes bloody)
Fever
Abdominal cramps
Nausea and vomiting
Headaches or body aches

Most healthy individuals recover in 4 to 7 days without medical treatment. However, in severe cases, the bacteria can spread from the intestines into the bloodstream, leading to septicemia, organ failure, or death without prompt medical care.

“Food safety is everyone’s responsibility. Preventing salmonella starts long before a product hits the shelf—it begins with understanding your sources, documenting your processes, and auditing every link in the chain. Our job is to make sure safety isn’t just a checkbox—it’s built into every decision.” Dedet Barroso, Director of FSQA at Source86.

Best practices for prevention

While the presence of salmonella in the environment is nearly unavoidable, contamination is preventable with proper controls. Here’s how the industry is stepping up:

Supplier vetting: Work only with farms and processors who follow Good Agricultural Practices (GAPs) and Hazard Analysis and Critical Control Points (HACCP) systems.
Routine microbial testing: Implement pathogen testing protocols for raw ingredients, finished products, and processing environments.
Sanitation and cleaning: Use validated sanitation procedures between production runs to prevent cross-contamination.
Cold chain management: Maintain proper refrigeration to limit bacterial growth.
Employee training: Reinforce hygiene and safe food handling with consistent training and performance monitoring.
Traceability systems: Use lot tracking and digital records to contain outbreaks quickly and efficiently.

Safeguarding your brand and your consumers

For manufacturers, importers, and foodservice brands, a salmonella outbreak isn’t just a health concern—it’s a full-blown operational risk. It threatens everything from retailer relationships to regulatory compliance to brand trust.

That’s why it’s critical to partner with suppliers who understand food safety from the ground up. From ingredient sourcing to private label packaging, risk mitigation must be built into every step.

Need help staying ahead of contamination risks?

At Source86, we work with food brands, manufacturers, and retailers to source and deliver safe, traceable ingredients with confidence. Our services include: