A somewhat surprising report out this week by the CDC reports for 2009 "sustained declines in the reported incidence of infections caused by Campylobacter, Listeria, Salmonella, Shiga toxin-producing Escherichia coli (STEC) O157, Shigella, and Yersinia." Only Vibrio seems on the rise. For E.coli O157:H7 infections, the CDC claims its "Healthy People 2010 target" was met.

The chart below shows the trend lines since 1996 in the reported incidence for many of these pathogens:

FIGURE 1. Relative rates of laboratory-confirmed infections with Campylobacter, STEC* O157, Listeria, Salmonella, and Vibrio compared with 1996-1998 rates, by year — Foodborne Diseases Active Surveillance Network (FoodNet), United States, 1996-2009†
 

While the news sounds good,(see Rick Goldfarb’s detailed analysis of the implications of the 2009 report for context) other factors could be at play that give only the appearance of a safer food system. One explanation can be found in a CDC report from 2009 that "in 2009, 10% fewer epidemiologists were working in state health departments than in 2006." The data the CDC has is only as good as the capacity the state health departments have on the ground to collect it. Fewer epidemiologists means fewer investigated food-borne illnesses. Fewer investigated food-borne illnesses means fewer reported food-borne illnesses. Fewer reported food-borne illnesses, therefore, does not necessarily mean the existence of fewer food-borne illnesses.