Dr. James L. Smith, a microbiologist with the U.S. Department of Agriculture, wanted to find out the answer to the question of why seniors are more at risk for fooborne illness.

So he reviewed data from foodborne outbreaks at nursing homes, and compared the immune and digestive systems of seniors and younger individuals as well as evaluating the overall physical well being of seniors. What he found is most interesting.

As we age, the ability of our immune system to function at normal levels decreases. The immune system is one of the most important mechanisms for fighting disease and preserving health, so a decrease in the level of disease-fighting cells is a significant factor in the number of infections that may occur.

In addition to the normal decrease in the function of the immune system as part of the aging process, undergoing major surgery also affects the body's ability to fight off infections.

To counteract the affects of aging on the immune system, long-term regular exercise is important.

As we age, inflammation of the lining of the stomach and a decrease in stomach acid occur. Because the stomach plays an important role in limiting the number of bacteria that enter the small intestine, a decrease or loss of stomach acidity increases the likelihood of infection if a pathogen is ingested with food or water.

Also adding to the problem is the slow down of the digestive process, allowing for the rapid growth of pathogens in the gut and the possible formation of toxins.

You maybe wondering what malnutrition has to do with foodborne illness. There is a connection. Malnutrition leads to increased incidence of infections, including those that result from foodborne bacteria.

There are many reasons why malnutrition occurs in seniors. There may be a decrease in the pleasure of eating. Medication, digestive disorders, chronic illnesses, physical disabilities or depression may result in a loss of appetite.

Good nutrition is an important factor in maintaining a healthy immune system.

Symptoms of Foodborne Illness

Common symptoms of foodborne illness include diarrhea, abdominal cramping, fever, sometimes blood or pus in the stools, headache, vomiting, and severe exhaustion. However, symptoms will vary according to the type of bacteria and by the amount of contaminants eaten.

Symptoms may come on as early as half-hour after eating the contaminated food or they may not develop for several days or weeks. They usually last only a day or two, but in some cases can persist a week to 10 days. For most healthy people, foodborne illnesses are neither long lasting nor life threatening. However, they can be severe in seniors.

If you suspect that you or a family member has foodborne illness follow these general guidelines:

1. Preserve the evidence. If a portion of the suspect food is available, wrap it securely, mark "DANGER" and refrigerate it. Save all the packaging materials, such as cans or cartons. Write down the food type, the date, and time consumed, and when the symptoms started. Save any identical unopened products.
2. Seek treatment immediately.
3. Call the local health department if the suspect food was served at a large gathering, from a restaurant or other food service facility, or if it is a commercial product.
4. Call the FDA Consumer Food Information Line at 1 (800-FDA-4010) if you have questions.