Raw chicken carries Salmonella because the bacteria live naturally in the intestinal tracts of poultry, often without making the birds visibly sick. Chickens can pick up Salmonella before they even hatch, carry it throughout their lives, and pass it to processing facilities where it spreads from carcass to carcass. National monitoring data from the USDA shows that roughly 7% of broiler chicken products at processing test positive for Salmonella, making it one of the most persistent food safety challenges in the meat supply.
Chickens Carry Salmonella Without Getting Sick
Salmonella bacteria have co-evolved with poultry to the point where they colonize the chicken’s gut, particularly the ceca (a pouch-like section of the lower intestine), without triggering obvious illness. A chicken can be heavily colonized and appear perfectly healthy. This is fundamentally different from how Salmonella affects humans. In people, as few as 1,000 to 100,000 bacterial cells can cause cramping, diarrhea, and fever. Chickens, by contrast, act as quiet reservoirs, shedding the bacteria in their droppings and spreading it to other birds, surfaces, and equipment.
Not all Salmonella strains pose equal risk. The serotypes Enteritidis, Infantis, and Typhimurium are responsible for the vast majority of human illnesses linked to chicken, even though they represent a small fraction of the Salmonella found on products. A 2024 risk assessment in the Journal of Food Protection estimated that these three high-virulence serotypes account for 69% to 83% of chicken-related Salmonella illnesses. Other common serotypes, like Kentucky, show up frequently on chicken but rarely make people sick.
Contamination Starts Before Hatching
Salmonella doesn’t just land on chickens from the environment. It can pass from a breeder hen directly to her eggs, a process called vertical transmission. Research on one strain, Salmonella Reading, found that 70% of breeder hens’ oviducts (the tube where the egg forms) and 40% of their ovaries tested positive. The bacteria contaminated the external eggshell surface in up to 70% of eggs, and in a small percentage of cases, the bacteria were inside the egg itself. This means chicks can hatch already colonized with Salmonella before they ever touch a barn floor.
Once hatched, chicks enter a farm environment full of additional exposure points. Salmonella persists in poultry litter (the bedding material on barn floors), in feed and water lines, and is carried by insects, rodents, and wild birds that enter or live near poultry houses. A flock that started clean can become colonized within days of placement in a contaminated barn. Because the bacteria survive well in dry, dusty conditions, even airborne dust from litter can spread it between birds.
Processing Spreads Bacteria Between Carcasses
Even if only a fraction of birds in a flock carry Salmonella, the slaughter process creates opportunities for the bacteria to spread. After birds are killed, their bacterial counts are at their highest. A study tracking contamination through a processing line found the peak Salmonella levels right after bleeding, at roughly 6.1 log colony-forming units per carcass (over a million bacteria). Subsequent steps like scalding and defeathering reduce those numbers, but the process of evisceration, where the internal organs are removed, creates a sharp rebound.
During evisceration, the intestines can tear or leak, releasing gut contents onto the meat surface. Researchers observed that the percentage of carcasses testing positive for Salmonella jumped from 10% to 40% during evisceration and the spray-washing step that follows it. The spray washing, intended to clean the carcass, can actually redistribute bacteria across the surface and onto nearby carcasses. This cross-contamination is why chicken parts (thighs, wings, breasts) tend to test positive at higher rates than whole carcasses. USDA data from 2016 to 2020 showed Salmonella incidence of 11.15% in chicken parts compared to 4.78% in whole carcasses, because cutting meat into parts creates more surface area and more handling.
Why Other Meats Are Less Affected
Chicken is more closely associated with Salmonella than beef or pork for several reasons. Poultry are slaughtered at much higher speeds, sometimes processing 140 birds or more per minute, which makes it harder to prevent intestinal contents from contacting meat. Cattle are larger, processed more slowly, and their hides are removed in a way that creates less contact between gut contents and edible surfaces. Poultry also have a higher natural rate of Salmonella carriage in their intestinal tracts compared to cattle. And because chickens are raised in large flocks in enclosed houses, the bacteria cycle efficiently through shared litter, air, and water, keeping colonization rates high before the birds ever reach the plant.
Antibiotic Resistance Adds Complexity
Some Salmonella strains found on chicken have developed resistance to multiple antibiotics. Surveillance data from 2020 through 2024 tested 132 Salmonella isolates from retail poultry in North Carolina and found 14 that were resistant to three or more classes of antibiotics. While that’s a minority of samples, multidrug-resistant strains are concerning because they’re harder to treat if an infection becomes severe enough to require antibiotics, which happens in about 5% of Salmonella cases, particularly in young children, older adults, and people with weakened immune systems.
What Kills Salmonella on Chicken
Salmonella is not especially hardy when exposed to heat. Cooking chicken to an internal temperature of 165°F, measured with a food thermometer in the thickest part of the meat, kills the bacteria reliably. The temperature matters more than visual cues like color or texture. Pink chicken cooked to 165°F is safe, while white chicken that hasn’t reached that temperature is not.
Cross-contamination in the kitchen is the other major risk. Salmonella from raw chicken transfers easily to cutting boards, countertops, hands, and other foods. Washing raw chicken under running water, a common practice, actually splashes bacteria onto surrounding surfaces and increases contamination risk. The CDC recommends against rinsing raw poultry. Instead, go straight from package to pan, wash hands thoroughly with soap and water after handling, and clean any surfaces that contacted the raw meat or its juices with hot soapy water.
Why Regulations Haven’t Eliminated It
Unlike E. coli O157:H7 in ground beef, Salmonella on raw poultry is not currently classified as an “adulterant” by the USDA, meaning its presence alone doesn’t make a product illegal to sell. In 2024, the USDA proposed a framework that would have declared certain Salmonella levels and high-virulence serotypes on raw chicken products to be adulterants, which would have given regulators the power to pull contaminated products. That proposal was withdrawn in April 2025, with the agency stating it needed to further assess its approach.
The practical result is that Salmonella on raw chicken is treated as an expected hazard that consumers are responsible for managing through proper cooking and handling. Processing plants are held to performance standards that track their Salmonella-positive rates over time, and national averages have improved, dropping from about 9% to under 7% between 2016 and 2020. But the bacteria’s deep integration into the poultry production chain, from breeder hens to hatcheries to barn floors to processing lines, means that eliminating it entirely from raw chicken remains far out of reach.