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. Choose ocean source seafood that is well cooked and served hot.