Salmonella poisoning is a bacterial infection of the intestines that causes diarrhea, fever, and stomach cramps, typically starting 6 hours to 6 days after eating contaminated food. It affects roughly 1.3 million people in the United States each year, leads to about 12,500 hospitalizations, and is the leading cause of death among foodborne pathogens, killing an estimated 238 Americans annually. Most cases resolve on their own within a week, but the illness can become serious in young children, older adults, and people with weakened immune systems.
How Salmonella Gets Into Your Body
Salmonella bacteria belong to a large family with over 2,500 identified strains. The two most common strains responsible for food poisoning worldwide are Enteritidis and Typhimurium. These bacteria live in the intestines of animals and spread to humans primarily through contaminated food.
The highest-risk foods are raw or undercooked poultry, eggs, ground meat, and unpasteurized milk or juice. But salmonella outbreaks have also been traced to fresh produce like tomatoes, sprouts, and leafy greens that were contaminated during growing or processing. You can also pick up salmonella from direct contact with reptiles, amphibians, or poultry (backyard chickens are a common source), or from touching contaminated surfaces and then your mouth.
Cross-contamination in the kitchen is another major route. Cutting raw chicken on a board and then using the same board for salad, or not washing your hands after handling raw meat, can transfer enough bacteria to cause infection.
What Happens Inside Your Gut
Once swallowed, salmonella bacteria travel to the small intestine and begin attaching to the cells lining the intestinal wall. The bacteria are remarkably aggressive invaders. They force intestinal cells to ruffle their outer membranes and essentially engulf the bacteria, pulling them inside. Within about 4 to 6 hours of entering a cell, the bacteria start replicating.
This invasion triggers a strong inflammatory response. Your immune system floods the area with fluid and immune cells to fight the infection, which is what produces the diarrhea, cramping, and fever. The inflammation is largely your body’s defense mechanism, not just the bacteria themselves causing damage.
Symptoms and Timeline
Symptoms usually appear between 6 hours and 6 days after exposure, with most people developing signs within 8 to 72 hours. The hallmark symptoms are:
- Diarrhea (sometimes bloody)
- Stomach cramps
- Fever
- Nausea and occasionally vomiting
The acute illness typically lasts 4 to 7 days. Diarrhea itself can persist for up to 10 days, and it may take several months for your bowel habits to fully return to normal. That lingering irregularity is common and doesn’t necessarily mean you’re still infected.
Who Faces the Greatest Risk
Healthy adults usually recover without medical intervention. The people most vulnerable to severe or invasive disease include infants, adults over 50 (especially those with cardiovascular disease), and anyone with a suppressed immune system. In these groups, salmonella can escape the intestines and enter the bloodstream, spreading to other parts of the body and causing infections in the urinary tract, joints, or other organs.
A small percentage of people develop reactive arthritis weeks after the initial infection. This causes joint pain, eye irritation, and painful urination that can last for months. It’s an immune-mediated response, meaning your own immune system continues reacting even after the bacteria are gone.
How It’s Diagnosed
If your symptoms are severe enough to warrant testing, the standard method is a stool culture. A lab grows bacteria from your stool sample on specialized plates and looks for colonies with the characteristic appearance of salmonella, then confirms the identification with additional testing. This process takes 18 to 24 hours. Newer molecular tests that detect the bacteria’s genetic material can provide faster results with greater sensitivity, and many labs now use these alongside or in place of traditional culture.
Treatment and Recovery
For most people, the only treatment needed is replacing lost fluids and electrolytes. Drink water, broth, or oral rehydration solutions to stay ahead of the fluid loss from diarrhea. Antibiotics don’t shorten the duration of diarrhea or fever in otherwise healthy people. In fact, using antibiotics unnecessarily carries real downsides: they can disrupt your gut bacteria, contribute to antibiotic resistance, and even prolong the period during which you carry and shed salmonella without symptoms.
Antibiotics are reserved for people with severe diarrhea, bloodstream infections, or infections that have spread beyond the intestines, and for those in high-risk groups like infants or immunocompromised individuals. If you fall into one of these categories and develop symptoms consistent with salmonella, getting tested promptly matters because treatment decisions depend on confirming the specific bacteria involved.
Preventing Salmonella at Home
Most salmonella infections are preventable with basic food safety practices. The single most important step is cooking food to the right internal temperature, measured with a food thermometer:
- All poultry (whole birds, breasts, thighs, wings, ground poultry): 165°F (73.9°C)
- Ground meats (beef, pork, veal, lamb): 160°F (71.1°C)
- Eggs and egg dishes: 160°F (71.1°C)
Beyond cooking temperatures, keep raw meat separate from ready-to-eat foods during storage and preparation. Wash cutting boards, utensils, and countertops with hot soapy water after they’ve touched raw meat or poultry. Wash your hands thoroughly after handling raw animal products, after touching reptiles or amphibians, and after contact with pet food or treats, which are occasionally recalled for salmonella contamination.
Refrigerate perishable foods within two hours of purchasing or cooking them. Salmonella multiplies rapidly at room temperature, so leaving food out, particularly during warm weather, gives bacteria the window they need to reach infectious levels.