**4.1 Current surveillance efforts in the United States**

In the United States, surveillance for *Salmonella* infections has been an ongoing effort since 1996. Managed by the CDC, the Foodborne Diseases Active Surveillance Network (FoodNet) collects active, population-based surveillance data on laboratory-confirmed infections for nine different pathogens that are commonly transmitted through food (as listed in *section 2.2*). These pathogens include *Campylobacter*, *Listeria*, *Salmonella*, *Shigella*, STEC O157, *Vibrio*, *Yersinia*, *Cryptosporidium*, and *Cyclospora* (the latter two are parasites). This surveillance effort includes 10 state health departments (i.e., California, Colorado, Connecticut, Georgia, Maryland, Minnesota, New Mexico, New York, Oregon, Tennessee), the U.S. Department of Agriculture's Food Safety and Inspection Service (USDA-FSIS), the Food and Drug Administration (FDA), and the CDC. The total surveillance area accounts for approximately 15% of the United States population, representing about 46 million people.

The national *Salmonella* database in PulseNet, which is the national molecular subtyping network for foodborne disease surveillance, was established by the CDC to subtype

The Burden of Salmonellosis in the United States 11

*Salmonella* prevention can be implemented in a number of ways, one of which is through environmental or system policies that improve regulation of potential sources of contamination. For example, the U.S. Department of Agriculture's Food Safety and Inspection Service currently recommends establishing facilities for irradiation of meats and eggs (USDA-FSIS, 2005). In addition, the need for improved sanitation inspection and supervision of abattoirs, food-processing plants, feed-blending mills, and egg grading stations is growing, as these are top sources of contamination for common foodborne pathogens in the United States (Batz *et al.*, 2011). Multiple regulatory outlets are currently responsible for monitoring different aspects of the U.S. food distribution chain. The Food and Drug Administration is responsible for the safety of approximately 80% of the nation's food supply, while other government entities, including the U.S. Department of Agriculture oversee the remainder. In covering such a broad enforcement responsibility, these agencies are continuously striving to reduce gaps in coordination and frequently collaborate on multiple efforts to ensure food safety. The World Health Organization (WHO) recommends strong communication, infrastructure, and coordination efforts among private, local, and federal regulatory sectors. The WHO also recommends the establishment of enhanced food safety standards in feed control regulation; cleaning and disinfection; vector control; and adequate cooking or heat-treating (including pasteurization or irradiation) of animalderived foods prepared for animal consumption (e.g., meat or bone or fishmeal and pet

The regulatory policies currently in place have been developed over many years in the United States. Starting in the early 1990s, farm-to-table egg safety efforts were developed by the Food and Drug Administration and the USDA Food Safety and Inspection Service (FSIS). Over the years, FSIS gained more regulatory authority in enforcing laws, including the Federal Meat Inspection Act (FMIA), the Poultry Products Inspection Act (PPIA), and the Egg Products Inspection Act. These particular laws or regulations required federal inspection and regulation of meat, poultry, and processed egg products prepared for distribution. In conjunction with these laws, the Food and Drug Administration and the FSIS conducted a joint *Salmonella Enteritidis* risk assessment in 1998. This assessment found that a broad-based policy encompassing multiple interventions from farm-to-table is more likely to be effective in eliminating egg-associated salmonellosis cases than a single policy

The lessons learned from the Food and Drug Administration (FDA) and the FSIS joint evaluation efforts contributed to the development and implementation of the FDA's new food safety strategy – coined as the "new egg rule" (Figure 4). This rule is considered very comprehensive and is aimed at preventing *Salmonella Enteritidis* in shelled eggs during production, storage, and transportation. Ironically, (as mentioned in section 2.1) one of the largest Salmonella outbreaks in U.S. history that led to a massive recall of about half a billion eggs and more than 2,000 reported illnesses occurred just prior to implementation of these new regulations during the summer of 2010 (Hutchison, 2010). The new egg rule requires production plants to implement intense rodent control, limits on contamination from people and equipment, regular egg tests, egg storage temperatures that retard *Salmonella* growth, and a requirement that egg producers maintain records documenting their compliance with these regulations. Modeled after several existing state programs (e.g., Pennsylvania Egg Quality Assurance Program), the new egg rule will, according to some farms, increase costs of production to about a penny per dozen (Hutchison, 2010). However, the Food and Drug

directed solely at one stage of the production-to-consumption continuum.

**4.2.1 Food distribution chain** 

foods). U.S. agencies follow these standards.

bacterial foodborne pathogens. PulseNet routinely subtypes *E. coli* O157:H7, nontyphoid *Salmonella* serotypes, *Listeria* monocytogenes, and *Shigella*. The database encompasses 46 states, two local public health laboratories, and the food safety laboratories of the Food and Drug Administration and the U.S. Department of Agriculture. The national database of pulsed-field gel electrophoresis (PFGE) for foodborne bacterial pathogens helps track potentially unrelated cases in isolated geographic areas and identifies outbreak strains.
