November 2006

Prevention of food- and water-borne diseases

Many illnesses, including traveller's diarrhoea, hepatitis A and typhoid are contracted through contaminated food and water. Travellers’ diarrhoea is the most common illness contracted abroad, affecting 20% to 60% of overseas travellers.
Travellers can reduce their risk of such diseases by following simple guidelines.

Water

In countries where sanitation may be poor it is advisable not to drink tap water or use it to clean teeth unless it has been treated. Ice should also be avoided.

Bottled carbonated drinks with an intact seal are usually safe, as are boiled water and hot drinks made with boiled water.

Water can be purified by bringing it to a boil. Although boiling is the most reliable it may not always be convenient. Chemical disinfectants such as iodine and chlorine preparations will usually kill bacteria and viruses. However, some parasites such as Giardia and Cryptosporidium may not be destroyed. In this instance combining filtration with a filter = 0.2-1.0 µm in size, plus halogenation should be effective.

Food

Certain foods are particularly prone to contamination and should generally be avoided. These include:

• Salads, as foods growing close to the ground, such as lettuce, are often contaminated.
• Uncooked fruits and vegetables, unless they have been peeled by the traveller
• Food that has be allowed to stand in lukewarm cabinets, or likely to have been exposed to flies such as may happen at open buffets
• Unpasteurised milk, cheese, ice cream and other dairy products
• Raw or undercooked seafood
• Food from street traders, unless it is served freshly prepared and hot on clean crockery

Do not assume that food served in good standard hotels is safe, as it may have been contaminated during preparation.

Travellers should be advised to eat only recently prepared food that is thoroughly cooked and served piping hot.

Hands should be washed after visiting the toilet, and always before preparing or eating food.

                   

                  Boil it, cook it, peel it or forget it!

Reference

World Health Organization. Preventing Travellers’ Diarrhoea: How to Make Drinking Water Safe. WHO/SDE/WSH/05.07. Geneva 2005. Available at:

http://www.who.int/water_sanitation_health/hygiene/envsan/

sdwtravel.pdf