This is a major cause of illness in travellers in particular travellers' diarrhoea. Unless certain of the purity of the local water supply, stick to boiled or bottled water and avoid ice in drinks. Alternatively, water can be sterilised with iodine drops/tablets or with a quality filter. Dishes and cutlery should ideally be washed with sterilised water. Hot tea, coffee, beer and wine are usually safe.

Ensure that milk has been pasteurised and that cheese, cream and ice cream are made from milk that has been pasteurised. Peel all fruit, eat only cooked vegetables and avoid salads.

Ensure that seafood, fish and meat are thoroughly cooked and eaten hot whenever possible. Avoid leftovers. Wash hands before eating or handling food and always after using the toilet.