The primary mission of the USDA, Agricultural Research Service, Poultry Microbiological Safety Research Unit is to develop technology preventing commensal intestinal colonization of chickens by human bacterial enteropathogens, including Salmonella and Campylobacter. The different mechanisms of colonization and the wide variety of sources of these pathogens combined with the different factors that affect host susceptibility to colonization indicate that a multifaceted research approach will be required to control Salmonella and Campylobacter during poultry production. The working hypothesis is that only by delivering chickens free of Salmonella or Campylobacter to the processing plant can significant reductions in the number and levels of contamination of chickens leaving the plant with these pathogens be achieved. As the means are developed to substantially reduce or eliminate the intestinal colonization of chickens by these pathogens, the pathogen-free chickens can be delivered to the processing plant, thereby eliminating or at least reducing the prevalence and levels of Salmonella on processed broilers.