Food & Water Precautions
Following strict food and water precautions while traveling in a developing country will decrease your risk of illness and disease. If food is thoroughly cooked and served hot, you can generally consider it safe. As a rule, eat hot food hot, and cold food cold.
- Avoid tap water and ice.
- It is best to avoid raw seafood or undercooked meat.
- Donít eat raw fruits or vegetables unless you have peeled, cooked or disinfected them. Contamination with soil, sewage or parasitic worms is common. Disinfect raw fruits and vegetables by soaking them for 15 minutes in a 10% bleach solution. Add 5 drops of household bleach for every quart of water.
- Avoid salad greens in restaurants unless you disinfect them yourself as above.
- Avoid unpasteurized dairy products (milk, yogurt, ice cream, custards, mayonnaise). As a rule, the label on products found in grocery stores will state whether the food has been pasteurized.
- Wash your hands prior to eating or handling food.
Only water that has been adequately disinfected (boiled, filtered and/or chemically treated) will protect you from viral and bacterial waterborne diseases. If boiled at sea level, water should be brought to a rolling boil for at least one minute and cooled. Tap water may be safe in hotels in large cities frequented by travelers, but when in doubt, drink treated water. In areas where water and sanitation are questionable, the following should be considered:
- Drink bottled water or boil or chemically disinfect and filter your water
- Use treated water to brush your teeth.
- If you use ice, make sure it is made from treated water.
- Beverages such as tea and coffee made from boiled water (or water brought to a high temperature over a period of time) are considered safe to drink.
- Chemically treat the water in your tanks (especially in warm climates) and test frequently (see section 4.2 and appendix I).
- Canned or bottled carbonated beverages including carbonated bottled water, soft drinks, beer and wine are considered safe to drink.
- When in a marina or near shore where sewage accumulates, do not use seawater to wash your dishes. Instead, use bleach and water rinse solution or rinse your dishes with boiling water.
- It is good to remember that in locations where water may be contaminated, ice should not be used in beverages. Alcohol does not decontaminate the ice. It is much safer to drink from a can or bottle than from a questionable glass. It is best to wipe the outside of the can or bottle before drinking from it.
For potable water stored in tanks, it is essential that chlorine be added to inhibit bacteria and algae growth (see below). Potable water includes tap water from known safe water sources as well as rainwater. Water made from water makers is generally safe to drink, although it may taste flat. Consider adding lime or lemon juice or a pinch of ascorbic acid to improve the taste. Remember that supplementing shore water with water made from a water maker will mix non-potable and potable water, and that the entire tank should then be treated.
For Potable Water From a Known Safe Water Source
Use the following chart for adding household bleach (5% sodium hypochlorite) to your potable water, as it will inhibit bacteria and algae growth in your tanks. It is recommended that you use a syringe that has increments in metric measurements, milliliters (mls). Note that mls are the same as ccís (cubic centimeters). Syringes can be purchased at most pharmacies. Beware that many countries are now stocking "ultra bleach" usually 7-7.5% hypochlorite. Try to read the label and try to stick with plain 5% sodium hypochlorite, which is standard household bleach. As it may be difficult to maintain a constant level of chlorine (3-5ppm), a simple swimming pool test kit may be useful. Iodine is not recommended because of health risks associated with the frequent and long-term use of iodine.
For Non Potable Water
To kill or remove harmful bacteria, viruses and organisms that may cause disease, water must be disinfected. The following method combines filtration to remove cyst organisms (e.g. cryptosporidium) and chlorination to kill the Giardia , bacteria and viruses.
- Before putting it in your tank, pre-filter shore water by running it through an in-line filter that removes sediment (available at Home Depot or similar hardware store).
- Install an in-line filter that filters Giardia , cryptosporidium and most (but not all) viruses (Amtec CBC-10, Katadyne or other ceramic filters with the same rating). Be aware that this may place undue stress on a water pump, so consider placing the pump so that it is pushing the water rather than pulling it through.
- Alternatively, use a gravity-feed ceramic filter (Katadyne, Berkfeld, Marathon [a division of MSR], or Aquarain). If you do not have a filter that filters the above organisms, you must treat your water with chlorine bleach.
- Install an in-line charcoal cartridge system that will remove the chlorine taste.
Use the following chart in for adding household bleach (5% sodium hypochlorite) to your tank water. This will remove remaining viruses and inhibit bacteria and algae growth.
Bleach Dosing For Water Tanks
Sodium Hypochlorite 5%, water measured in liters
|1 ounce = 30 cc||3.84 liter = 1 gallon|
|1 tablesoon = 15 cc||1 teaspoon = 5 cc|
|1 cc = 20 gtts (drops)||1 liter = 0.2604 gallon|
Water should be clear and allowed to stand for 30 minutes after application of bleach, prior to drinking. Add double the amount of bleach for cloudy or colored water. After treatment, water should have a slight chlorine odor. If not, repeat the dosage and allow treated water to stand for an additional 15 minutes. Maintain the recommended level of chlorine (3-5ppm) by checking the chlorine levels every two weeks, using a simple swimming pool test kit.
To use the chart, calculate the total number of liters or gallons you wish to treat. Then, read across to the amount in mlís of bleach you need to add to your tank.
|Liters of Water||ml or cc||Drops|
On Going Tank Maintenance
It is a good idea to sanitize your water tanks at least twice a year by mixing 1-teaspoon of liquid dish washing detergent and 1/8 cup of household bleach. After the solution is dissolved, pour it into your empty water tank(s). Add 5 gallons of warm water; rock the boat (if you can) to distribute the solution before opening each tap on board, including those in showers, until solution appears at the faucets. This is difficult with baffled tanks and large boats. Let the solution remain in the tank and lines for at least an hour to ensure good disinfecting. Open all taps and allow the solution to completely run out. Follow this by at least two full rinses of the tank. This, of course, is done when you have plentiful potable water supplies (Practical Sailor, December 1998, p.5).
I am in charge of water disinfection on our boat. I use a watermaker and add household bleach to our tanks prior to filling them or making water to inhibit bacteria and algae growth. To add bleach to each of our tanks, I first pour a small amount of bleach into a container and then draw up the necessary amount with a syringe. On the water tank next to the inspection port I have marked the amount of chlorine bleach (with an indelible marker) needed to disinfect a full tank of water. Thus, I never have to look up the amount of bleach I need to add to a full tank of water. If you do not have inspection ports, you will need to draw up the amount of bleach in your syringe and inject it into the fill ports. Chase it down with about a gallon of water to flush the bleach into the tank itself.
Jan Loomis is a registered nurse and paramedic who is currently cruising with her husband, Geoff Wickes, aboard their Valiant 40, Meridian Passage. She holds a faculty appointment at Oregon Health & Science University where she works in the emergency department and was formerly the coordinator of the Travel Medicine Clinic. She has sailed the Tasman Sea, Caribbean, Pacific Northwest, Kingdom of Tonga, Australia, and, most recently, Mexico and the Sea of Cortez.
James Bryan is a board certified emergency physician at the Portland Veteran's Affairs Medical Center and Oregon Health & Science University. He holds a PhD in Pharmacology and is the lead editor of the EMRA Guide to Antibiotic Use in the Emergency Department. He is an active member of the Wilderness Medical Society and has participated in wilderness search and rescue for over twenty-five years.
The Healthy Cruiserís Handbook, Prevention and Treatment Medical Resource Guide, is available from: Seaworthy Publications, 215 S. Park Street, Suite #1, Port Washington, WI 53074, (262) 268-9250,www.seaworthy.com
by Janette Loomis, RN, BS,
and James H. Bryan, MD, PhD
from: The Healthy Cruiserís Handbook, Prevention and Treatment Medical Resource Guide.