Precautions for travellers

If you are travelling overseas there are a number of precautions you can take for food and drink safety to help minimise the risk of health problems. Having safe drinking water/ beverages is very important, as local water may be untreated. Watching what foods you eat, where you buy them from and how they are prepared, can help avoid gastrointestinal upsets and illness. Personal hygiene around food safety and regular handwashing is essential. Vaccines are also available for prevention of some conditions, eg, hepatitis A.

Travel tips

The following are a number of basic tips that may help you avoid gastrointestinal problems when overseas.

Safe drinking

• Avoid tap water. Tap water in many areas is not safe. 
• Consider buying a good water filter for personal water supplies.
• Bottled water or canned fizzy drinks are available at most tourist destinations and should be consumed in preference to local water (make sure bottled water is a named brand and the seal has not been broken).
• Commercial wines and beers are usually reliable to drink; however, alcohol will not destroy all of the germs, just reduce their numbers.
• Check contents of commercial drinks because they may have unfamiliar concentrations of additives.
• Avoid ice in your drinks as it may have been made from untreated local water.
• Teas and coffees are usually OK provided the water has actually been boiled properly [but avoid milk unless pasteurised]. 
• Use purified water for brushing teeth - if it is not available, use carbonated water or hot-as-possible tap water.  
• The simplest way of purifying water is to boil it thoroughly. Bringing water to the boil, then letting it cool, is usually adequate for most needs. At high altitude, however, water boils at a lower temperature than at sea level so germs are less likely to be killed.
• Chlorine or iodine tablets/solutions (available from pharmacies and camping stores) can be used to purify water in some situations (see below)
• In general, remember to 'Purify it, pasteurise it, boil it or avoid it'.  

It is possible to purify water in three ways:

Boil water for at least 1 minute to destroy most gut pathogens (harmful bacteria, viruses, parasites) - this may be difficult in some situations. At altitude (>2000m), boil for 3 minutes or boil for 1 minute, cool water and follow with chemical treatment.

Filter water using microfilters - these vary in their effectiveness. In addition, water can be treated chemically.

Treat water chemically, using iodine or chlorine preparations:

• 2% iodine tincture - clear water (5 drops/litre, leave for 1 hour); cloudy water (10 drops/litre, leave for 1 hour)
• 10% povidone-iodine (eg, Betadine) - clear water (8 drops/litre, leave for 1 hour); cloudy water (16 drops/litre, leave for 1 hour)
• bleach - 2 drops of 5% bleach/litre of water, leave for 1 hour 
• chlorine tablets - 1 tablet/litre, leave for 10 minutes
• Iodine and chlorine generally eradicate most gut pathogens from water. They will not always kill Cryptosporidium or amoebic cysts, however. Very cold and cloudy water requires longer treatment times.

An iodine and chlorine taste, and iodine colour, can be removed from water by adding a few granules/litre of non-toxic sodium thiosulphate, or ascorbic acid (vitamin C), after the required purification time. 

Safe eating

• Clean your hands thoroughly with soap and water or a hand-sanitising solution or gel before preparing or eating food.
• If possible, eat a familiar diet for the first few days in a new destination (perhaps by taking foods from home) and adjust gradually to local foods. Check with customs officials before leaving home if taking food overseas.
• Try any new spices and unusual local foods in a controlled situation first (eg, a hotel).
• Eat well-cooked food only, but never reheated, especially with meats such as chicken, and seafoods like shellfish.
• Buy fresh, clean meat or poultry and do not use the same utensils for raw and cooked meats.
• Serve and eat food as hot as possible (bacteria grow quickly as food cools).
• Eat only fruits and vegetables you have washed and peeled yourself.
• Always wash raw vegetables before meal preparation, using a chemical wash (eg, povidone-iodine) then soak for 1 hour, or a few crystals of potassium permanganate in water and soak for 15-30 minutes.
• Avoid milk and milk products unless you know they have been pasteurised.
• Decline foods such as: leftovers, especially if they have been reheated; raw shellfish and sushi; cold cuts of meat; salads and peeled fruit.
• Shellfish may cause hepatitis A infection, and in areas with 'red tides' (algal blooms) may also contain poisonous biotoxins. They should be avoided in developing countries and after 'red tides'.
• Some species of fish (carnivorous reef fish) may be contaminated with ciguatera toxin, particularly if the fish are large or in a known ciguatera area, and should be avoided. This toxin causes a serious gastrointestinal and neurological illness.
• Nuts may be eaten with caution; however, they often contain alfatoxins from fungi, which can cause gastrointestinal upset. Alfatoxins in large quantities can damage the liver, so limit the amount eaten. Avoid nuts which are shrunken and misshapen, or have mould or sprouts.
• Do not eat food that has been kept at room or outside temperature for long periods or that has been exposed to flies, such as in restaurant buffets, markets and from street vendors. 
• In general, remember to 'Cook it, peel it, boil it or avoid it'.

Always check with your doctor or travel health professional before going overseas, as they will be able to give you recommendations and medications for many illnesses that you may contract from local food and drink.

Related topics

Also see: Travel vaccinations and Diseases spread by mosquitoes

Original content provided by myDr (2010) and Dr Marc Shaw, Medical Director, WORLDWISE Travellers Health Centres, New Zealand, from the Travel Medicine Guide, 6th edition, 2011. Edited by everybody, November 2011.