Foodborne illness an escalating concern

January 2008

In the past few years, an increasing number of reports of foodborne illness have made nationwide headlines. Although some people may dismiss this as only the result of improved reporting of such illnesses, a growing number of experts say the percentage of people affected by foodborne illnesses is increasing and the American public should be concerned about its food supply.

Herbert L. DuPont, MD, chief of internal medicine at St. Luke’s Episcopal Hospital in Houston and member of the Infectious Disease News editorial advisory board, said the escalating risk for foodborne illnesses is not a falsehood. A growing number of Campylobacter, Salmonella and Escherichia coli bacteria have entered the food chain and have caused outbreaks.

According to DuPont, more Americans are developing foodborne illnesses and numerous social, dietary and health factors may account for this increase.

DuPont, who published an article about food safety in a recent issue of Clinical Infectious Diseases, said an estimated 76 million cases of foodborne illness occur annually in the United States. These cases are of varying severity, but account for 325,000 hospitalizations and 5,000 deaths each year. DuPont also noted that the annual cost associated with infection due to the four most common bacterial enteropathogens acquired from contaminated food is about $7 billion.

Multiple causes

According to DuPont, various social changes in recent decades may be playing an important role in increasing the number of foodborne illnesses.

The increased prevalence of the mega-supermarket may be one factor. “During the 1950s, grocery stores in the United States stocked an average of 300 food items,” DuPont said. “This number grew 180-fold in the 1990s, to between 25,000 and 50,000 different food items.” A higher number of foods is associated with a greater likelihood that bacterial enteropathogens may be present.

Many of the foods found in these supermarkets are imported from other countries and may not be subject to the same level of inspection as foods originating in the United States. “Imported foods are an important part of the problem,” DuPont told Infectious Disease News. “Only about 2% of international foods are inspected.”

In the United States today, a greater percent of meals are consumed outside the home than ever before. Experts say this also may be a factor leading to an increase in the risk for foodborne illness. “More and more people are eating at commercial food service establishments,” DuPont said. “The risk for foodborne illness is greater when food is eaten in public restaurants rather than in homes.”

Finally, consumption of fresh fruits and vegetables has also increased. Although nutritionists laud this change as beneficial for Americans’ diets, infectious disease experts warn that such foods pose an increased risk for foodborne illnesses, particularly if consumed out of season or if they have not been grown locally.

To improve conditions

DuPont had several suggestions to help make the food supply safer and to reduce the risk for foodborne illness. DuPont said the Hazard Analysis and Critical Control Point (HACCP) system, currently used to help monitor and ensure the safety of the food supply in the United States, should be analyzed and, if necessary, revised.

“Validation of the effectiveness of the HACCP system should be undertaken, with identification of the most relevant critical control points through hypothesis-driven research,” DuPont said. “Methods for controlling contamination of produce are of greatest importance, requiring research to define routes of transmission and critical control points at all phases of the food production–consumption cycle.”

DuPont said the effectiveness of the HACCP system to secure food safety in restaurants is largely unknown. “Although all eating establishments are instructed by city and health departments to have an HACCP plan, the impact of these programs in preventing foodborne illness remains largely untested,” DuPont said.

DuPont said changes in the HACCP system may need to be made to reduce the risk for foodborne illness outbreaks that originate in commercial dining establishments. One suggestion would be to implement a grading system that evaluated each restaurant for various markers of food safety and hygiene. “In 1998, in Los Angeles County, a restaurant hygiene-grading program was implemented that used publicly posted grade cards,” DuPont said. “The grading program was associated with a 13.1% decrease in the number of foodborne-disease hospitalizations in the county during the two subsequent years of the study.”

Improvements in sanitation in homes could also help to reduce the risk of foodborne illness. “In ranking behaviors in the home that would lead to reduced foodborne illness, the use of a thermometer for cooking and increased hand washing in the kitchen were ranked as the two most important behavior modifications,” DuPont said. “In a study of home food-handling practices, a significant association was found between inconsistent hand washing and food preparation and an increased risk for sporadic salmonellosis in adults.”

DuPont also noted that the CDC recommends Americans to avoid certain foods that pose a particularly higher risk for foodborne illness, including unpasteurized milk and milk products, and certain raw or undercooked products, such as oysters, eggs, ground beef and poultry.

Food irradiation

Some infectious disease experts recommend food irradiation as a method to sanitize foods and reduce the presence of bacterial enteropathogens.

Food irradiation is a nonthermal method to reduce or eliminate pathogenic microbes in food. Although food irradiation remains an underused method throughout the world, it has been endorsed by the WHO, the CDC, the Department of Agriculture and the FDA.

DuPont said irradiation may offer the best method for reducing bacterial enteropathogens in high-risk foods such as poultry. However, he cautioned that more studies are needed before irradiation becomes the standard method to fight foodborne illness in all foods. “The specific foods for which the approach should be used and the specific methodology for decontamination have not been fully developed,” DuPont said. “A major issue in moving this concept forward is consumer acceptance of irradiated foods in the absence of public health laws and requirements. With efforts to educate the public about irradiation of food at the grocery store level, consumer acceptability is likely to improve.”

For more information:

• DuPont H. The growing threat of foodborne bacterial enteropathogens of animal origin. Clin Infect Dis. 2007;45:1353-1361.