Strengthening Foodborne Disease Surveillance and Improving the Safety of our Food Supply

By Craig Hedberg, Ph.D.
Associate Professor
Environmental Health Sciences
University of Minnesota
School of Public Health

This past year has seen an unprecedented array of national foodborne disease outbreaks, from E. coli O157:H7 in fresh-bagged spinach to Salmonella Tennessee in peanut butter. The scope of these outbreaks and the “wholesomeness” of the food vehicles associated with them raise considerable public concerns regarding the safety of the food supply, the ability of our public health system to rapidly detect these outbreaks, and the ability of our food regulatory agencies to prevent them.

Each of these areas presents challenges for evaluation and improvement. The farm-to-table supply chain for a simple meal may be more complex than the supply chain that built the car we drive to grocery store or restaurant. Multiple federal and state agencies are involved in regulating the production and distribution of food items and ingredients. Identifying the occurrence of a foodborne disease and finding its source requires advanced molecular characterization of the agent by public health laboratories. It also requires coordination between epidemiologists and environmental health specialists investigating the outbreak at local, state and federal levels.

Public Health Systems Research

Improving the safety of the food supply is an ongoing challenge that depends on good public health surveillance for foodborne disease. Surveillance can lead to detection and control of outbreaks directly. More importantly, it can lead to the identification of strategies to prevent future outbreaks. The Enteric Diseases Investigation Timeline Study (EDITS), led by Dr. Craig Hedberg was a groundbreaking effort to determine how long it takes for the public health system to identify and investigate individual cases and outbreaks of foodborne disease.

Funded by the Food Safety Office at the Centers for Disease Control and Prevention (CDC) through a cooperative agreement with the Council of State and Territorial Epidemiologists (CSTE), EDITS demonstrated that patients with foodborne diseases who seek medical attention, tend to do so within 3-4 days after onset of their illness, regardless of the cause. However, cases of E. coli O157:H7 infection tend to be reported and investigated several days sooner than do cases of Salmonella infection. Results suggest that physicians, laboratories and public health agencies all respond to E. coli O157:H7 infections with a greater sense of urgency. Despite the public health importance of these infections, the median interval from onset of symptoms to molecular subtyping by the public health laboratory is 15 days.

Improving Foodborne Outbreak Response

EDITS has given us a better understanding of how long it takes to detect widespread outbreaks of foodborne diseases. It also established a baseline for measuring improvements in our foodborne disease surveillance. Toward this end, CDC in partnership with CSTE, the Association of Public Health Laboratories (APHL) and the National Association of City and County Health Officials (NACCHO) established the Council to Improve Foodborne Outbreak Response (CIFOR).

On behalf of CIFOR, Dr. Hedberg is conducting two follow-up projects to build on the results of EDITS. These include the development of performance indicators for foodborne disease surveillance, and the development of guidelines for conducting multi-jurisdictional outbreak investigations. These projects will give local and state foodborne disease programs the tools they need to evaluate the effectiveness of their programs and to improve the efficiency and effectiveness of the complex outbreak investigations that are becoming all too common.

The projects will be used in combination with FoodSHIELD, an initiative of the National Center for Food Protection and Defense at the University of Minnesota. FoodSHIELD www.foodshield.org/ is a Web-based platform designed to create community between the various laboratories and regulatory agencies that make up our nation's food and agricultural sectors. It is funded by a grant from the National Integrated Food Safety Initiative (NIFSI).