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Freezing Zone Thermometer Macro Detail

After a disaster, there remains the overwhelming job of cleaning up. One of the biggest areas of concern is the safety of food and water.

Water After a Storm

After a major storm, assume that all water sources are contaminated until proved safe. Purify all water used for drinking, for cooking, and for washing utensils. Also purify the water used for washing hands, bathing, and cleaning kitchen and bathroom surfaces. Do not try to purify water that has a dark color, an odor, or contains floating material.

Disinfecting Water

To disinfect water, use one of the following methods:

  • Boil at a rolling boil for 5 minutes.
  • Add 1 teaspoon of unscented liquid chlorine bleach per 5 gallons of water. Make sure the bleach contains 4 to 6 percent sodium hypochlorite as its only active ingredient.
  • Add 12 drops of tincture of iodine per gallon of water.
  • Add water purification tablets according to directions on the package.

Thoroughly mix one of these solutions, and let the water stand at least 30 minutes before using. When using bleach, smell the water. The water should have a slight chlorine odor. If it doesn’t smell, repeat the treatment, wait 15 minutes, and smell again. To lessen the flat taste of boiled water, pour the water back and forth several times between two clean containers to add air.

Keeping Refrigerated and Frozen Food Safe

One main factor in keeping food safe is keeping it at the proper temperature. The only way you can know if your food is at the correct temperature is to use a thermometer. There are several types you need. One is a refrigerator/freezer thermometer. Place one in your refrigerator to assure the food is kept at below 40° F. Keep another of these thermometers in your freezer to ensure your food is kept at below 0° F.

Keeping Refrigerated Food Cold

In a refrigerator without power, food will remain chilled for up to 4 to 6 hours. This temperature will keep the longest if you don’t open the door of the refrigerator while the power is out. If you think the power will be out longer than this, add bags of ice to keep the temperatures cool longer. Place the ice on the upper shelves and pans on the lower shelves to catch the melting ice. The more ice you use, the longer the temperature will stay cool. Only open the door to add ice. Place a thermometer in the area farthest from the ice. Check the refrigerator temperature when adding ice. As soon as the power returns, check if food has been kept at below 40° F.

Keeping Food Frozen

When the power goes off, food will remain frozen in your freezer for several hours—maybe as long as several days. If your freezer is full and not opened during the power outage, the food will remain frozen for up to 2 days. If the freezer is only half full, food may stay frozen only 1 day. This time also depends on the seals in your freezer. If cold air is leaking around the seals, your food will thaw much faster. Replace loose gaskets now to help preserve your food when the power does go out in the future. The following are other factors that affect how long your food will
stay frozen:

  • The size of the freezer. The bigger the freezer, the longer the food will stay frozen.
  • The type of food in the freezer. Food with more water (fruits, vegetables, and meats) will stay frozen longer than food with little water (bread and nuts).
  • The insulation in the freezer. If your freezer has only a thin layer of insulation, food will thaw more rapidly.
  • The cavity depth of the freezer. The deeper chest-type freezers allow the food to remain frozen longer than upright freezers.

Cooking When the Power Goes Out

After a storm has knocked out electricity or gas lines, cooking meals can be hazardous if a few basic rules are not followed.

  • Never use charcoal or gas grills indoors. If you do, you risk asphyxiation from carbon monoxide and the chance of starting a fire that could destroy your home.
  • Always use camp stoves that use gasoline or solid fuel outdoors.
  • Use small electrical appliances if you have access to an electric generator with sufficient capacity.
  • Use wood for cooking in some situations.
  • Make sure the stovepipe has not been damaged if you’re cooking on a wood stove.
  • Build outside fires away from buildings. Never build a fire in a carport. Sparks can easily get into the ceiling and start a house fire.
  • Never use gasoline to start a wood or charcoal fire.
  • Contain any fire you build. A metal drum or stones around the firebed are good precautions. A charcoal grill is a good place to build a wood fire. Put out any fire when you are through with it.
  • Never leave an open fire, canned heat, or candle unattended. Keep children away at all times.

Evaluating Food

When your freezer and refrigerator are working again, evaluate the safety of the affected food. With frozen food, consider the type of food and the extent of thawing. For refrigerated food, consider the temperature inside the refrigerator before the return of power, the type of food, and the time these foods have been stored above 40° F. Use tables 1 and 2 when deciding which foods should be kept and which ones should be thrown out.

Cleaning Solutions

Mix together ¾ cup liquid bleach, 1 gallon warm water, and 1 tablespoon powdered laundry detergent. Apply this solution to surfaces. Keep them wet 5 minutes. Rinse with clean water. Wipe dry. This can also be used to help reduce mildew growth in large areas when you cleaned out mud and trash. Apply with a garden sprayer. Follow these guidelines when cleaning:

  • Remove loose dirt first so the bleach solution is reacting against the surface and not the dirt.
  • Change the bleach solution when the water appears cloudy or dirty.
  • Discard porous items such as plastic bowls, wooden spoons, or cutting boards if they have been submerged in floodwater.
  • Wear gloves when cleaning after storms.
  • Wear gloves to protect your skin when cleaning with chlorine bleach. Avoid splashing or spilling on clothing, furniture, hardwood floors, and rugs.

Getting Rid of Odors

Strong food odors may develop as a result of food spoilage during a power failure. Because the refrigerator or freezer must be empty and unplugged when cleaning, the best time to combat these odors is before restocking foods.

  1. Use one of the following solutions to wash interior walls of the refrigerator and freezer. Rinse with water and dry. Do not combine any of these household chemicals. Toxic fumes, which may be fatal, will result.
    • vinegar: 1 cup per gallon of water
    • household ammonia: 1 cup per gallon of water
    • chlorine bleach: ½ cup per gallon of water
  2. Take out all removable parts and wash with mild soap and water.
  3. Fill a large, shallow container with vinegar. Set in refrigerator or freezer several hours. If odor persists, let set 2 to 3 days, changing vinegar every 8 hours.
  4. Try activated charcoal to absorb lingering odors. Place the charcoal in large, shallow pans or paper in the bottom of the refrigerator and freezer. Leave for several days, changing the charcoal every few days. After the odor disappears, rinse and dry the interior before replacing food.

Food Exposed to Floodwater

Floodwaters may carry silt, raw sewage, oil, or chemical waste. Being prepared is the key to keeping food safe during a flood. Here are ways to prevent floodwater from coming in contact with food.

  • Raise refrigerators and freezers by placing cement blocks under their corners.
  • Move food from low cabinets.
  • Move canned goods and other food stored in a basement or lower level to a level above floodwaters, if possible.




Table 1. Evaluating Freezer Food

Freezer FoodPartially Frozen, some ice crystalsCompletely thawed still cold (below 40º F)Completely thawed warm (above 40º F)
meats (beef, veal, lamb, pork)refreezecook and serve or cook and refreezediscard
poultryrefreezecook and serve or cook and refreezediscard
organ meats (liver, kidney, heart)use within 48 hours; do not refreezecook and servediscard
fish and shellfishrefreezecook and serve or cook and refreezediscard
combination dishes (stews or casseroles, meat pies)cook and serve or cook and refreeze*cook and servediscard
dairy items (cream or cheese butter)refreezerefreeze or refrigeratediscard
produce (vegetables or fruit)refreezecook and serve or cook and refreezediscard
baked goods (bread, fruit pies, plain cakes)refreezerefreezeserve discard serve

*Refreeze only dishes containing raw ingredients. Do not refreeze previously cooked dishes.


Table 2. Evaluating Refrigerated Foods

Discard (if held above 40º F for more than 2 hours)Generally safe unrefrigerated
eggs, fresh or hard-boiledfruit juices (until power returns, but discard if cloudy, moldy, or fermented)
milkhard cheeses, butter, margarine (if well wrapped, but discard if mold or rancid odor develops)
fresh meats and poultryfresh fruits and vegetables (until power returns, but discard if mold, yeasty odor, or slimy texture develops
lunch meats and hot dogsopened containers of jelly, jam, mustard, ketchup, pickles, olives (safe unrefrigerated until power returns)
mayonnaise (opened)

While the video below mentions hurricanes in the title, the food safety information within the video is appropriate for many instances of severe weather.


 Trade and brand names used are given for information purposes only. No guarantee, endorsement, or discrimination among comparable products is intended or implied by the Alabama Cooperative Extension System. This publication is for information purposes only and should not be a substitute for recommendations or treatment by a health care provider.