Hurricane Sandy has left an estimated 7.5 million people without power, and in some areas, it could be days before it is restored.

U.S. Department of Agriculture recommends to keep meat, poultry, fish, and eggs refrigerated at or below 40 °F and frozen food at or below 0 °F. This may not be an easy thing to do when the power is out.

Here are some tips to prolong the life of your food, and the basics to know when it time to ditch items for good.

Shut the Door

The first rule of thumb is to keep the fridge and freezer doors closed as much as possible. The refrigerator will keep food safely cold for about 4 hours if it is unopened. A full freezer will hold the temperature for approximately 48 hours (24 hours if it is half full) if the door remains closed.

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You can get a block of ice --or even dry ice --to keep your refrigerator as cold as possible. Fifty pounds of dry ice should hold an 18-cubic foot full freezer for 2 days.

Keep an Eye on the Temperature

Use a thermometer to determine the temperature inside the fridge and freezer.  Remember that all perishable food should be kept below 40 degrees. In the event that perishable food is kept above 40 degrees for more than a total of 2 hours, bacteria will multiply rapidly.

If your food has come into contact with any flood waters and is not sealed in a waterproof container (that actually worked), then you will need to discard this food along with any other items that may have been contaminated like bottles, cutting boards, and others.

When in Doubt Throw it Out

Throw away any foods not in waterproof containers (ie, “those with screw caps, snap lids, pull tops, and crimped cans”) Foods commercially canned in metal or pouches can be wiped off and rinsed. Never do a ‘taste test’ to see if perishable foods like meat are still fresh. The last thing you need in a disaster scenario is to become ill.

Items such as raw or leftover cooked meat, poultry, fish, or seafood held above 40 °F for over 2 hours should be thrown out.  Also leftovers like casseroles, soups, stews or pizza should be ditched, as well as items like canned hams, or gravy should go.  Things that are okay to keep are opened jars of peanut butter, jelly, catsup, hard cheeses, opened juices, raw vegetables, rolls, cakes, muffins and tortillas.