Driven by consumer outrage following several food-related outbreaks that resulted in deaths, food safety legislation has toughened up in the United States. In addition, regional and national centers, principally the Centers for Disease Control and Prevention (CDC), have instituted nationwide food-related disease surveillance programs and new technologies. The result, as discussed by Patricia Griffin, MD, of the CDC, has been safer food and faster outbreak response.
The tragedy of the 1993 outbreak of Escherichia coli
0157:H7 traced to Jack in the Box restaurants in Midwestern US states was the first time pulsed-field gel electrophoresis (PFGE) was used to pinpoint the source of the infected beef and track the person-to-person transfer of the pathogen. Up until that point, investigations relied on the century-old tried-and-true culturing of bacteria. Although this approach still has its place, more modern techniques, like PFGE, allow for a molecular look at the pathogen, which enables matching of the DNA fingerprint of bacteria recovered from different locales and allows for the electronic transmission of the information to central repositories like the CDC.
“After the Jack in the Box outbreak, the US food safety system began catching up with major changes in food production that had started 50 years earlier. During the mid-1900s, meat producers created concentrated animal feeding operations to fatten animals before slaughter. Beef from hundreds of cattle was ground together to supply the proliferating fast-food hamburger chains,” said Dr. Griffin in her session. This production scheme was advantageous for producers, but created an environment where E. coli
-infected cow meat could potentially contaminate thousands of pounds of meat that would subsequently be shipped to a number of destinations.
The monopolization of food production has continued. “Today, four companies in each sector control 80% of cattle slaughtered and 50% of chickens processed. US food animals produce 500 million tons of feces per year versus 150 million tons produced by humans. Animal feces contain many human pathogens. The management of animal feces from concentrated animal feeding operations is loosely regulated,” Dr. Griffin explained.
There are an estimated 9.4 million foodborne illnesses annually in the United States, which result in an estimated 56,000 hospitalizations and an estimated 1350 deaths, according to the CDC. Of these, Salmonella
is responsible for an estimated 1.2 million cases; 23,000 hospitalizations; and 450 deaths. Aside from the human cost, the estimated annual US economic cost is $17 billion.
“The known pathogens may be the tip of the iceberg. CDC surveys estimate 140 million annual acute gastrointestinal illnesses not due to known pathogens. Many are likely foodborne,” Dr. Griffin said.