- Food- and waterborne illnesses are the most common causes of trip interruption.
- Diseases transmitted by improperly prepared or stored edibles may be due to viruses, bacteria, or parasites.
- Travelers most at risk are those who eat street food, eat at buffets, or drink water (including ice) or other beverages from a questionable source.
- Food- and waterborne illnesses can lead to diarrhea that ranges from mild/nuisance/minimal impact on plans to severe/necessitating change to itinerary.
- Preventive measures include observing hand hygiene (frequent, thorough handwashing), consuming foods that are fully cooked and served hot, eating thick-rinded peelable fruits, avoiding street food and buffets, avoiding unpasteurized dairy, and drinking only bottled or treated water and other beverages. Beverages should be served in sealed containers.
Guaranteeing the safety of food and beverages is difficult if not impossible when traveling, especially in developing countries. Without strict public health standards, bacteria or parasites in food or water may go undetected and cause illness such as travelers' diarrhea (TD).
However, travelers can continue to enjoy local foods, which is part of the pleasure of international travel. Although some evidence exists to suggest that where food is eaten is more important than what food is eaten, observing food and water precautions helps decrease the number of organisms ingested and the severity of TD if contracted. These precautions also help reduce the risk of other infections, such as dysentery, hepatitis A and E, giardiasis, typhoid, and paratyphoid. No reliable evidence exists for SARS-CoV-2 (cause of COVID-19) transmission from food or food packaging, despite reports to the contrary from China.
In developed countries, clean drinking water is available from the tap, and breakdowns in the system are rare. Developing countries, however, don't always have the resources needed to ensure a pure water supply; consequently, tap water is not safe to drink. Even if the local population can drink the water, travelers should not assume that they can. Residents have built up some immunity to organisms in the water, but visitors have not. As a result, tap water can make travelers sick.
Although it may not be possible to avoid diarrhea in certain high-risk destinations, even with the strictest adherence to preventive measures, the risk can be minimized by following the guidelines below when traveling through areas with less-than-adequate sanitation or with water sources of unknown purity.
Wash hands with soap and water for 20 seconds, especially before eating, after using the bathroom, and after touching potentially contaminated surfaces, regardless of the destination. If soap is not available, use disposable antiseptic wipes or an alcohol-based hand sanitizer containing at least 60% alcohol. Choose establishments that are known to cater to foreigners or that are specifically known by other foreigners to be safe. Foods that are safer to eat include breads, tortillas, crackers, biscuits, and other baked goods, as well as canned foods and fruits, nuts, and vegetables with thick skins, peels, or shells that can be removed. Food should be well-cooked and served steaming hot.
Avoid food from street vendors or market stalls. Avoid leafy or uncooked vegetables and salads. Some organisms in soil and water are not destroyed by normal cleaning methods. Beware of garnishes, which are typically uncooked vegetables, fruits, or herbs.
Avoid undercooked, raw, or cold meat, seafood, and fish, including large carnivorous fish (especially from reef areas because many contain concentrated toxins). See Seafood Poisoning.
Avoid unpasteurized dairy products such as cheese, yogurt, and milk. Be particularly wary of ice cream and other frozen confections that may have been made or stored in contaminated containers. Also avoid creamy desserts, custards, or sauces that may not have been adequately refrigerated, as well as cold sauces such as mayonnaise, salad dressing, chutneys, or salsas, which are usually raw and made by hand.
Avoid buffet foods such as lasagna, casseroles, and quiches, unless they are known to be fresh (not reheated) and have been kept steaming hot. Avoid buffets with no food covers or fly controls.
Continue to breastfeed infants because breastmilk is the safest food source for such infants.
Use sealed bottled water or chemically treated, filtered, or boiled water for drinking and for brushing teeth. Drink beverages made only with boiled water whenever possible (such as hot tea and coffee). Water brought to a boil (at or near sea level) is considered adequately disinfected but continue to boil vigorously for 1 minute for a margin of safety.
Drink canned, boxed, or commercially bottled carbonated water and drinks. International brands are safest. Beware of unsealed containers that may have been refilled. Beer and wine are safe to drink; however, alcohol added to other beverages does not render the beverages safe.
Purify water (see Treating Water ) if one of these options is not available. Decide which method to use for water purification and bring along the appropriate equipment or chemicals. Carry safe water if going out for the day in an area where availability of safe water is not assured. Do not assume that water is safe because it is chlorinated. Chlorination does not destroy all the organisms that can cause illness.
Avoid tap water or anything mixed with tap water and do not rinse toothbrushes in tap water. Do not drink fruit juice unless it comes directly from a sealed container; otherwise, it may have been diluted with tap water. Do not drink from wet cans or bottles because the water on them may be contaminated. Dry wet cans/bottles before opening and clean all surfaces that will have contact with the mouth. Do not use ice unless it is made from boiled, bottled, or purified water. Freezing does not kill the organisms that cause diarrhea.
If formula is used for feeding infants, prepare with boiled or distilled water and use sterilized containers.