Salmonella are spread by the fecal-oral route. Fecal material from infected humans or animals can get into our mouths in a variety of ways:
- consuming contaminated food or drink
- contact with the feces of infected humans, especially infants with diarrhea, that is not followed by proper hand washing
- direct contact with the feces of domestic or wild animals, including pets and farm animals, that is not followed by proper hand washing.
- Contact with contaminated pet food, especially raw pet food or pet treats which are at high risk of carrying Salmonella or other microbes, that is not followed by proper handwashing.
Pets may also have fecal matter on their hair, fur, feathers or skin that is transferred to our hands when we touch them. Salmonella live in the intestines of many animals including chickens, cows, pigs, sheep, and pets such as dogs, cats, chicks, ducklings, turtles, tortoises, snakes and iguanas. When animals are slaughtered for food, bacteria from an animal's intestines may contaminate the meat that we consume.
Common sources of infection are undercooked poultry and other meats, undercooked eggs and egg products, unpasteurized milk, and other contaminated food and water. During food preparation, bacteria can be transmitted from contaminated foods to other foods or surfaces in the kitchen. This is called cross-contamination. It is especially dangerous if foods that are meant to be consumed uncooked, such as fresh fruits or vegetables, are cross-contaminated. An example of this would be cutting raw poultry or meat on a cutting board and then cutting vegetables on the same board without washing and sanitizing the board in between.
Drinking water can be contaminated when humans, and wild or domestic animals leave their droppings in or near surface water sources such as springs, streams, rivers, lakes, ponds or shallow wells.