Author(s): Brigette Gleason, Vincent Hill, Patricia Griffin

Contaminated food and water pose a risk for travelers. Many infectious diseases associated with contaminated food and water are caused by pathogens transmitted via the fecal–oral route. Additional information on pathogens associated with travelers’ diarrhea, prophylaxis, and treatment options can be found in Sec. 2, Ch. 6, Travelers’ Diarrhea.

Food

Travelers should select food with care. Travelers should follow food safety practices recommended in the United States while abroad. Raw food is especially likely to be contaminated. Raw or undercooked meat, fish, shellfish, and produce can be contaminated with pathogens, and some fish harvested from tropical waters can transmit toxins that survive cooking (see Sec. 4, Ch. 10, Food Poisoning from Marine Toxins).

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. Advise travelers to rinse produce with safe water (see Sec. 2, Ch. 9, Water Disinfection); washing with water alone, however, does not remove all pathogens from produce. Foods of animal origin, including meat and eggs, should be cooked thoroughly, and travelers should select pasteurized milk and milk products, including soft cheeses. In restaurants, inadequate refrigeration and lack of food safety training among staff can result in transmission of pathogens or their toxins. Consumption of food and beverages obtained from street vendors increases the risk of illness. In general, fully cooked foods that are served hot and foods that travelers carefully prepare themselves are safest.

Travelers should not 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 as they do for restaurants.

Clinicians should advise travelers to wash their hands with soap and water before preparing or eating food, after using the bathroom or changing diapers, before and after caring for someone who is ill, and after contact with animals or animal environments. When soap and water are not available, travelers should use an alcohol-based hand sanitizer containing ≥60% alcohol, then wash hands with soap and water as soon as possible. Hand sanitizer is not as effective as handwashing for removing some germs, like Cryptosporidium or norovirus, and does not work well when hands are visibly dirty or greasy. The Centers for Disease Control and Prevention (CDC) website Handwashing: Clean Hands Save Lives provides additional information.

Feeding Infants

Breastfeeding

For infants aged <6 months, the safest way to feed is to breastfeed exclusively. Practicing careful hygiene when using a breast pump can reduce the risk of getting germs into the milk. For details, see How to Keep Your Breast Pump Kit Clean: The Essentials. For information on malaria prophylaxis for breastfeeding patients see Sec. 5, Part 3, Ch. 16, Malaria, and Sec. 7, Ch. 2, Travel & Breastfeeding.

Formula

For infants who get formula, parents should consider using liquid, ready-to-feed formula, which is sterile. When preparing formula from commercial powder, following the manufacturers’ instructions usually is sufficient. Although no powdered formula is sterile, travelers should consider packing enough for their trip because manufacturing standards vary widely around the world.

Formula safety can be increased by reconstituting powder using hot water (≥158°F; ≥70°C); instruct travelers to pack a food thermometer to test water temperature, especially for infants <3 months of age and those with weakened immune systems. Prepared formula should be used within 2 hours of preparation or refrigerated for a maximum of 24 hours. After feeding, any remaining liquid or prepared formula should be discarded.

For more on infant feeding hygiene, see How to Clean, Sanitize, and Store Infant Feeding Items and Cronobacter: Prevention & Control.

Water

Swallowing, inhaling aerosols of, and having contact with contaminated water can transmit pathogens that cause diarrhea, vomiting, or ear, eye, skin, respiratory, or nervous system infections. Travelers should follow safe water practices recommended in the United States while abroad.

Drinking Water & Other Beverages

In many parts of the world, particularly where water treatment, sanitation, and hygiene are inadequate, tap water can contain disease-causing agents, including bacteria, viruses, parasites, or chemical contaminants. Consequently, tap water might be unsafe for drinking, preparing food and beverages, making ice, cooking, and brushing teeth. Infants, young children, pregnant people, older people, and immunocompromised people (e.g., those with HIV or on chemotherapy or certain medications) might be especially susceptible to illness.

Travelers should avoid drinking or putting tap water into their mouths unless they are reasonably certain the water is safe. Similarly, travelers should avoid ice since it may have been prepared with tap water. Box 2-05 provides tips and recommendations of other safe water and beverage practices for travelers.

Recreational Water

Pathogens that cause gastrointestinal, respiratory, skin, ear, eye, and neurologic illnesses can be transmitted via contaminated recreational freshwater or marine water. Water from inadequately treated pools, hot tubs, spas, or water playgrounds, including splash pads or spray parks, can also be contaminated. Recreational water contaminated by human feces from swimmers, animal waste, sewage, 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. Infectious pathogens (e.g., Cryptosporidium) can survive for days, even in well-maintained and safely operated pools, water playgrounds, and hot tubs and spas. To protect other people, children and adults with diarrhea should not enter recreational water.

Maintaining proper pH and free chlorine or bromine concentration is necessary for preventing transmission of most infectious pathogens in water in pools, water playgrounds, and hot tubs or 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 3–10 parts per million (ppm) in hot tubs and spas (4–8 ppm if bromine is used) and 1–10 ppm in pools and water playgrounds (2–10 ppm for aquatic venues using cyanuric acid as a chlorine stabilizer). Travelers can purchase test strips at most superstores, hardware stores, and pool supply stores.

Pseudomonas, which can cause “hot tub rash” or “swimmer’s ear,” and Legionella (see Sec. 5, Part 1, Ch. 9, Legionnaires’ Disease & Pontiac Fever) can multiply in hot tubs and spas in which chlorine or bromine concentrations are not adequately maintained. Travelers at increased risk for legionellosis (e.g., people ≥50 years of age, those with immunocompromising conditions), should avoid entering or walking near higher-risk areas (e.g., hot tubs, spas). Travelers also should avoid pools, water playgrounds, and hot tubs or spas where bather limits are not enforced or where the water is cloudy. Additional guidance can be found at CDC’s Healthy Swimming website.

Travelers should not swim or wade near storm drains; in water that could be contaminated with human or animal feces, sewage, or wastewater runoff; in lakes or rivers after heavy rainfall; in water that smells bad, looks discolored, or has algal mats, foam, or scum on the surface; in freshwater streams, canals, or lakes in schistosomiasis-endemic areas of Africa, Asia, the Caribbean, and South America (see Sec. 5, Part 3, Ch. 20, Schistosomiasis); in water that might be contaminated with urine from animals infected with Leptospira (see Sec. 5, Part 1, Ch. 10, Leptospirosis); or in warm seawater or brackish water (mixture of fresh and sea water), particularly when they have wounds.

Travelers with open wounds should consider avoiding all water contact. Seawater and brackish water can contain pathogens (e.g., Vibrio spp.) that can cause wound infections and sepsis. 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. If travelers with wounds do plan water contact, they should cover the wound with a water-repellent bandage.

Naegleria fowleri is a parasite found around the world in warm freshwater, including lakes, rivers, ponds, hot springs, and locations with water warmed by discharge from power plants and industrial complexes. To help prevent a rare but fatal infection caused by this parasite, travelers should hold their noses shut or wear a nose clip when swimming, diving, or participating in similar activities in warm freshwater. Travelers also should avoid digging in or stirring up sediment, especially in warm water. Clinicians should inform travelers that Naegleria fowleri infection also has been linked to use of contaminated tap water for sinus or nasal irrigation.