US food-safety legislation has toughened up as both regional and national centers strive to provide the public with safe food through the use of food-related disease surveillance programs and new technologies.
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.
Globally, the World Health Organization estimates that there are 600 million foodborne illnesses each year, with 40% of them occurring in children younger than 5 years. Annually, an estimated 420,000 people die of these foodborne illnesses.
“Foodborne illness is important. Everyone must eat. An increasing proportion of the population is vulnerable, such as the elderly and immunocompromised. There is no vaccine; [however,] illnesses are preventable, often with simple measures,” Dr. Griffin stressed in her session.
In the 1990s, legislation was enacted that mandated the recall of contaminated beef and safer hamburger preparation by food outlets. In 1996, the CDC launched two programs—PulseNet and FoodNet—to detect outbreaks using techniques like PFGE and to monitor the effectiveness of meat safety programs. These programs have helped drive the decline in foodborne infection and, combined with epidemiologic investigations, have reduced the response time to outbreaks. The quicker response time has decreased the human toll caused by these outbreaks.
Subsequent illness outbreaks due to bacterial contamination of spinach and processed food, such as peanut butter, led to the passage of the Food Safety Modernization Act on January 4, 2011—which is about to come into effect. The act, which shifts the focus of food safety from outbreak response to outbreak prevention, is the most sweeping reform of US food safety laws in over 70 years, is about to come into effect.
Challenges that remain include the use of antibiotics as growth supplements in large-scale commercial cattle-, swine-, and chicken-raising facilities. As of this December, antibiotics can no longer be sold for growth promotion. In addition, at present, there is no routine ongoing surveillance on farms; this is a major public health gap.
“Investigation of outbreaks usually stops outside the farm gate, so we don’t learn what to do differently,” said Dr. Griffin. The CDC has embraced the use of whole genome sequencing, which provides information on the entire genome of pathogens. “Whole genome sequencing refines investigations by determining which isolates are highly related. This can tie isolates from earlier years to an ongoing source,” said Dr. Griffen explained.
The driving vision of the CDC, according to Dr. Griffin, is that everyone has a right to safe food.
Progress Toward Building a Better U.S. System for Tracking, Investigating, and Decreasing Foodborne Illnesses; Patricia Griffin, MD, Centers for Disease Control and Prevention, Atlanta, Georgia
Brian Hoyle, PhD, is a medical and science writer and editor from Halifax, Nova Scotia, Canada. He has been a full-time freelance writer/editor for over 15 years. Prior to that, he was a research microbiologist and lab manager of a provincial government water-testing lab. He can be reached at email@example.com.