When drinking bottled beverages, surfaces which come in direct contact with your mouth, should first be wiped clean. Brush teeth and rinse toothbrush with bottled, boiled or treated water. Boiling is the most reliable method for making water safe to drink. Bring to a vigorous rolling boil for one minute and allow to cool to room temperature. At very high altitudes, above two kilometers, longer boiling or chemical disinfection will be necessary.
Chlorine is less reliable than iodine for chemical disinfection.
Food should be selected with care. All raw food is subject to contamination. Eat only cooked food that is still hot, or fruit that you peeled yourself. Avoid all raw seafood. Avoid shellfish that may come from polluted water.