A current review (Emerg Med Clin North Am. 2008;26:475-497) details the three main causes of foodborne illness: “microscopic pathogens” (bacteria, parasites, fungi, viruses), “toxic contaminants” (heavy metals, chemicals, pesticides), and “toxic substances naturally present” (poisonous mushrooms and other plants, fish, shellfish).
The author notes that viral or bacterial contaminants are by far the most common and cites recent CDC FoodNet—Foodborne Diseases Active Surveillance Network (www.cdc.gov/foodnet/) data which indicate that “while foodborne infections from a number of common pathogens continue to decline, including Campylobacter, Listeria, Shigella, and Yersinia, infections caused by Shiga toxin-producing Escherichia coli O157:H7 (STEC) and Vibrio infections have remained constant or increased.”
Hemolytic uremic syndrome (HUS) caused by E. coli O157:H7 can result in potentially fatal acute renal failure, particularly in children. Outbreaks in recent years have been linked to undercooked ground beef, unpasteurized cider, and contaminated fresh spinach. Immunocompromised individuals, e.g., dialysis patients, transplant recipients, and those with liver disease, are especially susceptible to a sepsis syndrome caused by Vibrio, a bacterium that is found in contaminated water and carried by shellfish or crabs. Patients should be cautioned to avoid eating undercooked or raw shellfish, particularly oysters.
The CDC acknowledges that “making food safe in the first place is a major effort, involving the farm and fishery, the production plant or factory, and many other points from the farm to the table.” Pasteurization and wider use of food irradiation are highlighted as important technologic methods to this end. Although good manufacturing practices and regulatory oversight are essential, consumers can also take steps to improve food safety.
Recommendations to reduce the risk of foodborne diseases outlined by the National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK) and the CDC include:
- Wash hands with soap and warm water before and after food preparation.
- Cook meat, poultry, and eggs thoroughly to kill harmful bacteria—to at least160ºF for ground beef (no pink in the middle) and until egg yolks are firm.
- Separate foods to avoid cross-contamination. Wash preparation surfaces, utensils, and cutting boards after contact with raw foods and before using with other foods. Keep raw meat, poultry, fish, and their juices separate from foods that are ready-to-eat. Put cooked foods on clean platters, not back on those previously used for raw meats.
- Chill leftovers promptly (within two hours or less) to inhibit the growth of bacteria. Place leftovers in shallow containers so that food will cool more quickly.
- Clean fresh fruits and vegetables by rinsing them under running tap water. Remove and discard the outer leaves of cabbage and lettuce. Since the cut surface of produce promotes bacterial growth, avoid leaving cut fruits and vegetables at room temperature for long periods.
- Buy foods that have been processed for safety (i.e., pasteurized milk and fruit juices/ciders).
- Report suspected foodborne illness to your local health department.
Additional information is available at digestive.niddk.nih.gov/ddiseases/pubs/bacteria/ and www.cdc.gov/ncidod/dmd/diseaseinfo/files/foodborne_illness_FAQ.pdf, both accessed February 2, 2009.