Updated

People in Hurricane Isabel's (search) wake must take special precautions to ensure they're eating safe food and drinking safe water, federal health officials warned Friday.

The Food and Drug Administration's (search) advice:

--Refrigerated food shouldn't go above 40 degree Farenheit. The refrigerator will keep food cold for about four hours if unopened. A full freezer will hold the temperature for about 48 hours -- 24 hours if half full -- if the door remains closed. Buy dry or block ice to keep your refrigerator as cold as possible. Fifty pounds of dry ice should hold an 18-cubic-foot full freezer for two days.

--Once power is restored, evaluate the food -- but not by tasting. If an appliance thermometer was kept in the freezer and reads 40 F or below -- or if each package still contains ice crystals -- the food is safe to refreeze or cook. Discard any perishable food, such as meat, poultry, fish, eggs and leftovers, that has been above 40 degrees for two hours.

--Listen for local instructions about the purity of area tap water.

--Absent local instructions, if you're not sure whether water is safe to drink, bring it to a rolling boil for one to three minutes. If you can't boil, add 8 drops of newly purchased, unscented liquid household bleach per gallon of water, stir well and let the water stand for 30 minutes before using. Or use water-purifying tablets.

--Wash fruits and vegetables with water from a safe source.

--For infants, use baby formula that doesn't require adding water if possible, or use bottled water to prepare formula if tap water is potentially contaminated.

--Don't eat food that came into contact with flood water, including food stored in containers with screw-caps, snap lids or that were home-canned. Discard wooden cutting boards, plastic utensils, baby bottle nipples and pacifiers that came into contact with flood waters, as they can't be completely disinfected. Wash metal or ceramic dishes and any undamaged, commercially canned foods, removing the cans' labels -- and then sanitize dishes and cans in a solution consisting of a quarter-cup bleach per gallon of water.

Health officials add that children should never play in floodwaters, which may be contaminated by sewage.

Also, areas infested with West Nile virus could see an increase in the mosquito-borne illness because of flooding. Drain standing water wherever possible, wear long pants and long sleeves, and use a bug repellant containing DEET (search), federal officials cautioned.