Established in 1995 following a deadly E. coli O157 outbreak linked to contaminated hamburgers, which caused over 700 confirmed infections and 4 child deaths, the Foodborne Diseases Active Surveillance Network (FoodNet) emerged as a critical early-warning system for food safety threats. Operated by the Centers for Disease Control and Prevention (CDC) in collaboration with the U.S. Department of Agriculture (USDA), Food and Drug Administration (FDA), and 10 state health departments, FoodNet monitors laboratory-confirmed infections across a surveillance area covering 15% of the U.S. population (approximately 48 million people).
Active Surveillance Methodology
FoodNet employs active surveillance, distinguishing it from passive reporting systems. Personnel at sites in Connecticut, Georgia, Maryland, Minnesota, New Mexico, Oregon, Tennessee, and selected counties in California, Colorado, and New York routinely contact clinical laboratories to identify and audit cases of nine key pathogens:
- Salmonella
- Campylobacter
- Shiga toxin-producing E. coli (STEC)
- Listeria
- Vibrio
- Yersinia
- Shigella
- Cyclospora
- Cryptosporidium (through 2017)
For every confirmed infection, FoodNet collects demographic data, hospitalization status, survival outcomes, and travel history. This systematic approach enables accurate incidence calculations (cases per 100,000 people annually) and trend analysis.
Table: Key Pathogens Under FoodNet Surveillance
| Pathogen | Primary Transmission | Unique Surveillance Features |
| Salmonella | Food, animals, environment | Most frequent cause of infections |
| STEC 0157 | Contaminated food/water | Linked to hemolytic uremic syndrome (HUS) |
| Campylobacter | Undercooked poultry, unpasteurized milk | Top cause of enteric infections |
| Listeria | Ready-to-eat foods | High mortality rate |
| Vibrio | Raw shellfish | Increasing coincidence since 2016 |
Data Tools and Public Impact
FoodNet’s online platform, FoodNet Fast, provides interactive access to:
1. Pathogen Surveillance Tool: Tracks illness rates since 1996
2. Diagnostic Laboratory Practices Tool: Monitors testing changes for 10 pathogens
3. HUS Surveillance Tool: Follows pediatric kidney failure linked to STEC since 1997
4. Population Survey Tool: Analyzes food consumption and exposure patterns
Annual “report card” summaries published in the Morbidity and Mortality Weekly Report (MMWR) serve as benchmarks for regulatory agencies. For example:
- Declines in E. coli O157 and HUS incidence validated ground beef safety improvements.
- Stagnant Salmonella rates prompted USDA performance standards for poultry.
- Rising Vibrio and Yersinia cases (partly attributed to advanced diagnostic testing) highlight emerging challenges.
Adapting to Modern Challenges
FoodNet continually evolves to address diagnostic shifts, such as increased use of culture-independent diagnostic tests (CIDTs), which detect pathogens faster but may reduce bacterial isolates needed for outbreak investigations. In 2023, FoodNet expanded surveillance to all of Colorado, improving representation of Hispanic, Indigenous, and rural populations.
As the only U.S. system dedicated to comprehensive tracking of sporadic foodborne infections, FoodNet’s data, collected at an annual cost under $7 million, informs policies impacting a food safety system that prevents billions in potential economic losses.
