Food Safety Crucial for People with Lowered Immunity

by Food and Drug Administration (FDA)

People with AIDS have a greatly increased risk of serious illness or death from food-borne infections. This isn't theoretical. It's medical fact. But it's also fact that they can protect themselves by eating defensively.

— Peter Hawley, M.D., medical director
Whitman-Walker Clinic, Washington, D.C.

Food-borne microorganisms cause tens of millions of cases of intestinal illness each year in the United States. For most healthy people, the distressful vomiting, abdominal cramps, and diarrhea are blessedly short-lived. But in people with weakened immunity, such as those with AIDS (acquired immune deficiency syndrome), symptoms are often severe, and the infections are so difficult to treat they can be fatal.

What's Bugging the Food?

The leading cause of bacterial diarrhea in the United States, Campylobacter jejuni bacteria, induces up to 10 percent of all cases. Of the patients infected with this bacterium, about 1 in 1,000 dies. Half of the C. jejuni infections are associated with eating or handling chickens. Indeed, surveys show the bacterium contaminates from 20 to 100 percent of retail raw chickens. Other prime sources are unpasteurized milk, non-chlorinated water, and cross-contamination — as can occur, for instance, from using the same cutting board to cut up raw chicken and then vegetables without cleaning in between.

"The second most frequent bacterial offender is probably the more familiar Salmonella bacterium, causing roughly 2 million to 4 million salmonellosis cases annually," says Wallace Garthright, Ph.D., a mathematician with the Food and Drug Administration's biometric and risk assessment branch, Center for Food Safety and Applied Nutrition.

Individuals with AIDS, and possibly late-stage HIV (human immunodeficiency virus) infection, are at least 20 times more likely than other people to become infected with Salmonella and six times more likely to develop a blood infection, which can be life-threatening. In late-stage HIV disease, including AIDS, campylobacteriosis and salmonellosis tend to recur and are extremely difficult to treat.

Salmonella bacteria frequently contaminate unpasteurized milk and raw poultry, meat and eggs. Up to 40 percent of marketed raw chickens carry this bacteria. Garthright emphasizes that cross-contamination from raw poultry to other foods during storage or food preparation is a major pathway for Salmonella into the diet.

Of the several types of Listeria bacteria, the only one responsible for illness in people is Listeria monocytogenes. AIDS patients are 200 to 300 times more susceptible to listeriosis than the general public, according to Peter Hawley, M.D., of the Whitman-Walker Clinic. Besides bloodstream infection, listeriosis can lead to meningitis (inflammation of the membranes covering the brain and spinal cord) and encephalitis (inflammation of the brain itself).

The bacteria are found in unpasteurized milk; cold smoked fish, poultry and meat; undercooked poultry; and certain cheeses, particularly soft-ripened varieties such as Brie and Camembert. Even vegetables can carry Listeria and, once cut, support its growth. A quarter of the estimated 1,600 listeriosis cases each year end in death.

Hepatitis A can be transmitted by unsanitary food handling or by eating raw or undercooked shellfish harvested from contaminated waters. One-cell parasites such as Giardia lamblia, found mainly in water, also infect HIV-positive individuals and people with AIDS. The extent to which people with HIV infection are more at risk for each of these illnesses is unknown, but some scientists believe that any infection may hasten the progression from less severe HIV disease to AIDS.

"The longer someone with HIV disease maintains good overall health and avoids food-borne infection and other illness, the better are the person's chances to receive possible effective treatment not yet developed or available," says Douglas Archer, Ph.D., deputy director of FDA's foods center.

Dos and Don'ts

Common-sense precautions in food selection and preparation can significantly lessen the hazard of infection from contaminated food. According to Hawley, a cardinal rule is: "Any raw animal-derived food must be considered to be contaminated with harmful microorganisms. Under no circumstance should a high-risk person consume unpasteurized milk or raw or undercooked eggs, poultry, fish, shellfish or meat."

The following food safety precautions are smart advice for anyone, but they're especially important for people whose health is compromised, including those infected with HIV, cancer patients, diabetics, transplant recipients, infants, pregnant women, and the elderly.

Check displays, labels, and containers.

Look for cleanliness at meat and seafood counters and salad bars. For example, cooked shrimp lying on the same bed of ice as raw fish could be contaminated.

Buy only Grade A or better eggs. Avoid eggs that are cracked or leaking. Don't buy any foods whose "sell by" or "best used by" date has passed. Read the label to see whether a food contains raw or undercooked animal-derived ingredients. Caesar salad dressing, for instance, traditionally uses raw eggs. Buy only milk and cheeses labeled "pasteurized." (Firms may sell cheese made of raw milk provided it has been aged for over 60 days. To be safe, AIDS patients should avoid this as well.)

Keep groceries safe.

Put raw seafood, poultry and meat in plastic bags so drippings can't contaminate other foods in the shopping cart or bag.

Take groceries directly home and refrigerate cold foods. Hot foods from the deli should be eaten, kept hotter than 60 degrees Celsius (140 degrees Fahrenheit), or refrigerated right away. Leaving foods unrefrigerated for even a few hours fosters bacterial growth.

Store eggs in their original carton in the main section of the refrigerator. Don't put them in the egg section of the door because the temperature there is higher.

Be meticulously clean.

About the Author

www.fda.gov
FDA is A United States government body that oversees medical devices, including contact lenses, intraocular lenses, excimer lasers and eyedrops. In the US, these products must be approved by the FDA before they can be marketed.