Food Safety Guidelines

by Leslie Hanna

Nausea, vomiting and diarrhea that occur in response to something eaten, colloquially called "food poisoning," are familiar to most people. Caused by ingesting food-borne bacteria, viruses or toxins, gastrointestinal infections are fairly common in the general population and are usually transient. However, they may be life-threatening in a person with AIDS, particularly someone with late-stage disease. Certain bacterial or viral infections may become chronic or recurrent, causing additional immune suppression, wasting and death. Treatments are often aimed at reducing symptoms rather than curing the infection, so prevention is crucial.

Three of the most common food-borne bacteria that cause illness are Salmonella, Listeria and Campylobacter. Symptoms of infection with Salmonella, or salmonellosis, develop 6-48 hours after exposure and may last up to a week in HIV negative persons. These bacteria can cause severe illness in people with HIV. Symptoms include nausea, vomiting, abdominal cramps, diarrhea, fever, headache and muscle pain. The foods most often associated with salmonellosis are raw or undercooked meat, fish, poultry and eggs.

Infection with Listeria, or listeriosis, causes similar symptoms, which may appear 2-30 days after exposure. Listeria can infect the bloodstream (bacteremia) and the central nervous system, causing meningitis (inflammation of the meninges, the membrane that encases the spinal cord and brain) or encephalitis (inflammation of the brain). Listeria are found in unpasteurized dairy products and raw or undercooked meat, poultry and fish.

The symptoms of Campylobacter infection are similar (nausea, diarrhea, headache, muscle pain, fever), although abdominal pain may be more severe. Symptoms generally begin 2-5 days after exposure and last 7-10 days. Campylobacter is found most often in raw or undercooked poultry, unpasteurized milk and milk products, and nonchlorinated water. Not all tap water is free of bacteria; check local water safety standards for more information.

Since most food-borne illnesses result from improper food handling, the risks can be greatly reduced by implementing proper food handling procedures. The following guidelines apply to anyone wishing to reduce such risks, and are especially important for people with HIV.

Food Shopping

Food labels should always be checked. Make sure that juice, milk and cheese products are pasteurized (heat-treated to kill microscopic organisms). Check the "sell by" and "best used by" labels on all products. Avoid products that contain raw or undercooked (rare) meat or dairy products. When purchasing meat, poultry or fish, place them in a plastic bag before placing them into a shopping cart with other items, to reduce the risk of bacterial cross-contamination.

Avoid products that are displayed unsealed (e.g., cooked shrimp displayed on a bed of ice alongside other seafood), and do not purchase anything with damaged packaging. Deli sections are potential hotbeds for bacteria, since raw and cooked foods are often prepared on the same counter and displayed together. Avoid cross-contamination between raw and cooked foods at home as well as at delis.

After shopping, properly store chilled or frozen foods as soon as possible. Foods kept in a car or at room temperature for only an hour or two may begin to grow bacteria.

At Home

Most cases of food-related infection occur as a result of food handling or preparation at home. It is crucial to keep shelves, countertops, refrigerators, stoves, sinks, utensils, sponges, towels and brushes clean. Cutting boards, countertops and cookware/utensils (i.e., anything that comes into contact with raw or undercooked foods) can be sterilized using a highly diluted (1:100) bleach solution. Use plastic cutting boards, which are easier to sterilize, instead of wooden ones. Fresh fruits and vegetables can be cleaned in a mild bleach bath and should be peeled if possible. Always wash hands before and after handling food.

Proper cooking is one of the main ways to avoid contamination, since heat kills bacteria. Consult cookbooks for proper cooking temperatures and times, and use a meat thermometer. Cook red meat until it is well done. Eggs should be thoroughly cooked, not runny.

Microwave cooking involves special requirements. Most microwave recipes require a "standing time" that ensures that the proper temperature spreads throughout the food. Consult a microwave cookbook for details on proper use.

Another tactic is to avoid uncooked or undercooked foods by themselves or as components of other food preparations. Eggs should be assumed to be contaminated, and it is best to avoid anything containing raw or undercooked eggs, including raw cookie dough, cake batter, eggnog, Hollandaise sauce and Caesar salad or other dressings made with raw eggs. Eggshells should also be regarded as contaminated. They should be disposed of properly and hands should be washed after handling them. By the same token, do not prepare dishes that require raw or undercooked fish (ceviche, sushi or sashimi) or meat (steak tartar).

Refrigerator temperature should be kept at or below 40 degrees Fahrenheit. Food stored in the refrigerator should be in covered containers. Thoroughly heat pre-cooked foods or leftovers.

Eating Out

Restaurants, like grocery stores, are required by state and local health departments to follow sanitation guidelines. The basic rule of thumb is to avoid high-risk foods both in restaurants and at home. Some restaurants now prepare special Caesar salad dressing made without raw egg, but check thoroughly to make sure such claims are legitimate.

Always order food well done, and check by slicing into the center of a steak or other piece of meat to make sure that it is not pink or bloody. If it is, send it back to be thoroughly cooked.

Avoid raw seafood such as sushi, sashimi and oysters on the half shell, and undercooked seafood, such as lightly steamed mussels, snails or oysters. Well-done fish should be flaky, not rubbery.

Adapted from "Eating Defensively: Food Safety Advice for Persons with AIDS." Department of Health and Human Services Publication No. FDA 92-2232.

Leslie Hanna is Associate Editor of BETA.