How long is food safe during a power outage?

“I like these cold, gray winter days. Days like these let you savor a bad mood.”
-Bill Watterson (author of Calvin & Hobbes)

My wife & I recently spent several winter days without power due to the Oct 29 snow storm which dropped 4 inches of heavy wet snow on trees still covered with autumn leaves. This causes massive amounts of broken limbs, fallen trees, and power lines knocked down. The damage to power lines was greater than tropical storm Irene a few months back.

When the power went out on Saturday we knew it would be gone for awhile - this was a major storm. So our first thought was the fridge. We discussed what to pull from the fridge (before opening it) and then quickly removed items we wanted to use and put them in an insulated cooler. The fridge and freezer were not opened again until power was restored. The cooler was placed outside in the snow to help keep it cold. If we had been more clever we might have emptied the fridge and put everything in the snow. This would have been great overnight but perhaps still unsafe during the heat of day. We also could have used dry ice in the fridge but no one was distributing it locally to us.

The magic temperature with refrigerated food is 40°. The USDA says,

"Always keep meat, poultry, fish, and eggs refrigerated at or below 40°F and frozen food at or below 0°F." ... "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."

The USDA website has a table listing when foods are no longer safe. Discard any potentially hazardous food that has been above 41°F for four hours or more, reached a temperature of 45°F or higher for any length of time, or has an unusual color, odor, or texture.

VERY IMPORTANT: More than 250 diseases can be caused by bacteria found in contaminated food. Many bacteria can grow above 40°F and not produce a funny smell or taste. Never taste food to determine if it’s safe.

The following items can tolerate room temperatures for a few days and DO NOT need to be tossed out:

• Butter or margarine
• Hard and processed cheeses
• Fresh uncut fruits and vegetables, Fruit juices
• Dried fruits and coconut
• Opened jars of vinegar-based salad dressings, jelly, relish, taco sauce, barbecue sauce, mustard, ketchup, olives and peanut butter
• Fresh herbs and spices
• Fruit pies, breads, rolls, and muffins. Cakes, except cream cheese frosted or cream-filled
• Flour and nuts

Fortunately the list above describes most of our fridge content.  We should toss our raw eggs and our yogurt. I always thought yogurt would last longer than regular milk but even yogurt has a short shelf life; see http://www.ehow.com/facts_7382133_long-yogurt-stay-good-unrefrigerated_.html

Bottom Line
Perishable food such as meat, poultry, seafood, milk, and eggs that are not kept adequately refrigerated or frozen may cause illness if consumed, even when they are thoroughly cooked.

For a list of foods and which are "safe" or not when warm, check out http://www.fsis.usda.gov/factsheets/keeping_food_Safe_during_an_emergency/index.asp
Another good site is http://www.uri.edu/ce/ceec/food/factsheets/powerout.html

See also my blog post:  Living without power