Food & Water Precautions

Contaminated food and water often pose a risk for travelers. Many of the infectious diseases associated with contaminated food and water are caused by pathogens transmitted via the fecal–oral route. Swallowing, inhaling aerosols of, or coming in contact with contaminated water—including natural freshwater, marine water, or the water in inadequately treated swimming pools, water playgrounds (splash parks or splash pads), or hot tubs and spas—can transmit pathogens that can cause diarrhea, vomiting, or infection of the ears, eyes, skin, or the respiratory or nervous system.

Food

Advise travelers to select food with care. Raw food is especially likely to be contaminated. Raw or undercooked meat, fish, and shellfish can carry various intestinal and systemic pathogens. (Some fish harvested from tropical waters can transmit toxins that survive cooking; see Food Poisoning from Marine Toxins in this chapter.) In areas where hygiene and sanitation are inadequate or unknown, travelers should avoid consuming salads; uncooked vegetables; raw, unpeeled fruits; and unpasteurized fruit juices. Fruits that can be peeled are safest when peeled by the person who eats them. Produce should be rinsed with safe water (see Water Disinfection in this chapter). Foods of animal origin, including meat and eggs, should be thoroughly cooked; milk and milk products, including milk used in soft cheese, should be pasteurized. In restaurants, inadequate refrigeration and lack of food safety training among staff can result in transmission of pathogens. Consumption of food and beverages obtained from street vendors has been associated with an increased risk of illness. In general, foods that are fully cooked and served hot are safest, as are foods people carefully prepare themselves.
Travelers should wash their hands with soap and water before preparing food, before eating, after using the bathroom or changing diapers, before and after caring for someone who is ill, and after contact with animals or their environments. If soap and water are not available, use an alcohol-based hand sanitizer (with ≥60% alcohol) and wash hands with soap and water as soon as they become available. Hand sanitizer is not very effective against Cryptosporidium or norovirus and does not work well when hands are visibly dirty or greasy.
The safest way to feed an infant aged <6 months is to breastfeed exclusively. If the infant is fed formula prepared from commercial powder, the powder should be reconstituted with hot water at a temperature of ≥158°F (≥70°C). This precaution will kill most pathogens with which the infant formula may have been contaminated during manufacturing or through handling after opening. To ensure that the water is hot enough, travelers should prepare formula within 30 minutes after boiling the water (see Water Disinfection in this chapter). The prepared formula should be cooled to a safe temperature for feeding (for example, by placing the bottle upright in a bath of safe water and safe ice [see below], keeping the bath water below the nipple ring) and used within 2 hours of preparation. Bottles and nipples should be washed and then sterilized (in boiling water or in an electric sterilizer). Travelers may wish to pack enough formula for their trip, because manufacturing standards vary widely around the world.
Tell travelers not to bring perishable food from high-risk areas back to their home country without refrigeration. Moreover, travelers should exercise the same cautions about food and water served on flights that they do for restaurants.

Water

Drinking Water and Other Beverages

In many parts of the world, particularly where water treatment, sanitation, and hygiene are inadequate, tap water may contain disease-causing agents, including viruses, bacteria, and parasites, or chemical contaminants. As a result, tap water in some places may be unsafe for drinking, preparing food and beverages, making ice, cooking, and brushing teeth. Infants, young children, pregnant women, the elderly, and people whose immune systems are compromised (for example, because of HIV, chemotherapy, or transplant medications) may be especially susceptible to illness.
Travelers should avoid drinking or putting into their mouths tap water unless they are reasonably certain it is safe. Many people choose to disinfect or filter their water when traveling to destinations where safe tap water may not be available. Tap water that is safe for drinking is still not sterile and should not be used for sinus or nasal irrigation or rinsing, including use in neti pots and for ritual ablution unless it is further disinfected by the traveler. Tap water should never be used to clean or rinse contact lenses. Water that looks cloudy or colored may be contaminated with chemicals and will not be made safe by boiling or disinfection. In these situations, travelers should use bottled water if it is available.
In areas where tap water may be unsafe, only commercially bottled water from an unopened, factory-sealed container or water that has been adequately disinfected should be used for drinking, preparing food and beverages, making ice, cooking, and brushing teeth. (See Water Disinfection in this chapter for proper disinfection techniques.)
Beverages made with water that has just been boiled, such as tea and coffee, are generally safe to drink. When served in unopened, factory-sealed cans or bottles, carbonated beverages, commercially prepared fruit drinks, water, alcoholic beverages, and pasteurized drinks generally can be considered safe. Because water on the outside of cans and bottles may be contaminated, they should be wiped clean and dried before opening or drinking directly from the container.
Beverages that may not be safe for consumption include fountain drinks or other drinks made with tap water and iced drinks. Because ice might be made from contaminated water, travelers in areas with unsafe tap water should request that beverages be served without ice.

Recreational Water

Pathogens that cause gastrointestinal, respiratory, skin, ear, eye, and neurologic illnesses can be transmitted by contaminated recreational water in inadequately treated pools, water playgrounds (splash pads or spray parks) or hot tubs/spas, or in freshwater or marine water. Recreational water contaminated by human feces from swimmers, sewage, animal waste, or wastewater runoff can appear clear but still contain disease-causing infectious or chemical agents. Ingesting even small amounts of such water can cause illness. To protect other people, children and adults with diarrhea should not enter recreational water. Infectious pathogens, such as Cryptosporidium , can survive for days even in well-maintained pools, water playgrounds, and hot tubs/spas.
Maintaining proper pH and free chlorine or bromine concentration is necessary to prevent transmission of most infectious pathogens in water in pools, water playgrounds, and hot tubs/spas. If travelers would like to test recreational water before use, CDC recommends pH 7.2–7.8 and a free available chlorine concentration of 2–4 ppm in hot tubs/spas (4–6 ppm if bromine is used) and 1–3 ppm in pools and water playgrounds. Test strips may be purchased at most superstores, hardware stores, and pool supply stores. Pseudomonas , which can cause “hot tub rash” or “swimmer’s ear,” and Legionella (see Chapter 4, Legionellosis) can multiply in hot tubs and spas in which chlorine or bromine concentrations are not adequately maintained. Travelers at increased risk for legionellosis, such as the elderly and those with immunocompromising conditions, may choose to avoid entering or walking near higher-risk areas such as hot tubs/spas. Travelers should avoid pools, water playgrounds, and hot tubs/spas where bather limits are not enforced or where the water is cloudy. Additional guidance can be found at www.cdc.gov/healthywater/swimming.
Travelers should not swim or wade 1) near storm drains; 2) in water that may be contaminated with sewage, human or animal feces, or wastewater runoff; 3) in lakes or rivers after heavy rainfall; 4) in freshwater streams, canals, and lakes in schistosomiasis-endemic areas of the Caribbean, South America, Africa, and Asia (see Chapter 4, Schistosomiasis); 5) in water that might be contaminated with urine from animals infected with Leptospira (see Chapter 4, Leptospirosis); or 6) in warm seawater or brackish water (mixture of fresh and sea water) when they have wounds.
A traveler with an open wound should consider staying out of the water or covering the wound with a water-repellent bandage (often labeled “waterproof”), as seawater and brackish water can contain germs, such as Vibrio spp., that can cause wound infections. If a sore or open wound comes into contact with untreated recreational water, it should be washed thoroughly with soap and water to reduce the chance of infection.
Naegleria fowleri (www.cdc.gov/parasites/naegleria) is a parasite found in warm freshwater around the world. To help prevent a rare but fatal infection caused by this parasite, travelers should hold their nose shut or wear a nose clip when swimming, diving, or participating in similar activities in warm freshwater (including lakes, rivers, ponds, hot springs, or locations with water warmed by discharge from power plants and industrial complexes). They should also avoid digging in or stirring up sediment, especially in warm water. This infection has also been linked to use of contaminated tap water for sinus and nasal irrigation.

Bibliography

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Authors

Patricia M. Griffin, Vincent Hill