May 28, 1999

Food-Related Illnesses

More than 250 different diseases have been described that can be caused by contaminated food or drink. The most common foodborne diseases are infections caused by bacteria, such as Salmonella and Campylobacter, or by the Norwalk family of viruses. A foodborne disease outbreak is defined as a group of people developing the same illnesses after ingesting the same food. Most cases of foodborne disease are single cases not associated with a recognized outbreak. The great majority of food items which cause foodborne diseases are raw or undercooked foods of animal origin such as meat, milk, eggs, cheese, fish or shellfish.

Every year, in the United States foodborne infections cause millions of illnesses and thousands of deaths. Most infections go undiagnosed and unreported. Some foodborne diseases such as botulism and trichinosis are becoming less common, while others such as salmonellosis are becoming more common. Thus, the spectrum of foodborne disease is changing. New infections not previously known to be foodborne diseases are emerging. Approximately 600-700 foodborne related complaints are reported each year to the Bureau of Epidemiology. Not all outbreaks or diseases are equally likely to be reported, and many cases of foodborne diseases are sporadic.

To prevent contracting foodborne diseases, the consumer can do the following: 1) Make sure that food from animal sources (meat, diary, eggs) is thoroughly cooked or pasteurized. Avoid eating such foods raw or undercooked. 2) Be careful to keep juices or drippings from raw meat, poultry, shellfish or eggs, from contaminating other foods. 3) Do not leave potentially contaminated foods for extended periods of time at temperatures that permit bacteria to grow. Promptly refrigerate leftovers and food prepared in advance.

Thorough cooking kills almost all foodborne bacteria, viruses and parasites, and is the single most important step in preventing foodborne disease. Preventing spread of contamination from raw foods in the kitchen is also important. Washing one's hands, cutting board, and knife with soap and water immediately after handling raw meat, raw poultry, raw seafood or raw eggs will help keep the food handler from contaminating any other foods in the kitchen. Persons who are ill with diarrhea or vomiting should not prepare food for others. Special care is needed in the preparation of food for infants, the elderly, and persons whose immune systems are compromised by underlying illness or medical treatment of illness.

While foodborne diseases, their causes and effects are better understood today, emerging risks need to be monitored for several reasons. First, the food supply of the United States is changing dramatically, The conditions under which food animals are raised have changed greatly. We now import 30 billion tons of food a year, including fruit, vegetables, seafoods, and canned goods; these imported foods are an increasing proportion of the diet, and often come from developing countries where food hygiene and basic sanitation is less advanced. Food processing technologies are constantly evolving. The centralization of the food industry means that a single contaminated product may appear in many different foods and many different forms, and infect a considerable number of people before it is identified. Second, consumers are changing; there are increasing numbers of elderly or immunosuppressed persons who are at higher risk of severe illness; consumers spend less time cooking than before, and may have received less instruction in food handling in home or school than before.

Finally, new and emerging foodborne pathogens have been identified, which can cause diseases unrecognized 50 years ago. These include bacteria, parasites, and viruses, along with toxic causes of foodborne illnesses. Constant vigilance is necessary to identify new problems requiring new solutions as they emerge. However, despite these new risks, the food supply of the United States is probably safer now than ever.