Foodborne and Waterborne Illness: Nutritional Considerations

Foods of animal origin, particularly meat and eggs, are most often implicated in cases of foodborne illness.⁹ Scientists at the CDC's Foodborne and Diarrheal Diseases Branch have observed that foodborne illness starts near the bottom of the food chain in the form of contamination of animal feed with Salmonella enterica.¹⁰ Other investigators working with the Food and Drug Administration's (FDA) Division of Animal and Food Microbiology Office have documented that resistant strains of salmonella are common in retail ground meats, including ground chicken, beef, turkey, and pork.¹¹

Consumers may believe that choosing white meat in place of red meat will reduce their risk for foodborne infection. However, a multistate investigation linked an outbreak of listeria to processed turkey meat, resulting in a recall of 16 million pounds of the product.¹² Eating chicken in restaurants has been noted as the most common cause of infection with campylobacter, a bacterium that is a common cause of gastroenteritis in the United States.¹³

Raw oysters and other shellfish eaten by approximately 10% of adults each year may be a source of vibrio vulnificus gastroenteritis if harvested from contaminated waters, particularly the Gulf of Mexico.¹⁴ The US Department of Agriculture's (USDA) Food Safety and Inspection Service listed eggborne infection with Salmonella enteritidis as an important public health problem in the United States in 2000.¹⁵ However, the problem appears to be ongoing, partly as a result of food-handling practices and specifically due to ingestion of products containing undercooked eggs, such as mayonnaise, ice cream, and custards.

In addition, better food handling will not prevent infections passed in intact eggs.¹⁶ The USDA's Animal Disease Research Unit has found that dairy farms are a potential source of Listeria monocytogenes, a zoonotic foodborne pathogen that is responsible for 28% of U.S. food-related deaths every year.¹⁷ Other studies have found that dairy farms are also a reservoir for multidrug-resistant Salmonella typhimurium,¹⁸ E coli (O157:H7),¹⁹ and Yersinia enterocolitica,²⁰ as well as other pathogenic organisms.²¹

Produce may become contaminated with fecal pathogens during planting, irrigating, harvesting, processing, and shipping, or through contaminated water.²²

Food-service establishments can be a frequent source of foodborne infection, although the risk is also present in homes and any other setting that allows for poor temperature control in preparing, cooking, and storing food.⁹ A 2005 survey of food-service personnel found that more than 50% did not always wear gloves while touching ready-to-eat foods; almost 25% did not follow appropriate hand-washing guidelines; more than 33% did not always change gloves between handling raw meat and ready-to-eat foods; and more than 50% did not use a thermometer to check food temperatures.²³ All these precautions should be used in any setting where food is prepared.

The CDC, FDA and USDA have established the Foodborne Diseases Active Surveillance Network (FoodNet) as a component of the CDC's Emerging Infections Program (EIP). FoodNet's purpose is to monitor trends in foodborne diseases, determine the societal burden caused by these diseases, and assess which diseases are attributable to specific foods and settings in the United States. Data listed on FoodNet's Web site clearly indicate that the routine practice of using antibiotics in animal feed selects for the development of antimicrobial resistance.²⁴ The site lists U.S. farms and dairies in violation of guidelines to avoid antibiotic use. Tracing the origin of contaminated meat by FoodNet is complicated by the fact that a single hamburger might contain meat from many cows and that the beef is handled at multiple facilities.¹ These factors make it extremely difficult to identify the origin of contamination. Extensive research into flash gamma irradiation has shown effective eradication of bacterial contamination. However, low public acceptance has resulted in slow implementation of this process.²⁵

Orders

See Basic Diet Orders chapter.

What to Tell the Family

Complete avoidance of foodborne illness may not be possible. However, risk can be minimized through proper cooking and handling to avoid cross-contamination. Risk is further reduced by avoiding foods of animal origin. However, certain plant foods may also be contaminated during production, processing, or handling.

In the case of immunocompromised patients, ingestion of raw fish and raw meat is associated with a higher risk of foodborne illnesses. Patients with chronic liver disease should be strongly encouraged to avoid raw shellfish, including oysters, clams, and shrimp.