Shigella can be transmitted to individuals through the ingestion of contaminated foods. Even though the food may look and smell normal it may be infected with Shigella. Food can become contaminated from infected food handlers that fail to wash their hands with soap after using the restroom. Vegetables may also be a source of contamination by harvesting from sewage-contaminated fields. Shigella can be transferred to food by flies. Flies may breed in infected feces and then contaminate food by alighting on the food. Another common mode of transfer to humans is by drinking or swimming in contaminated water either from water fountains, swimming pools and lakes. Shigella are not transferred through air, only by direct contact.