As many as 10 million people could lose power this week as Hurricane Sandy clobbers the East Coast. That means a lot of games of Monopoly by candlelight -- but it also means a lot of spoiled food as fridges and freezers stop working.
Some cautious folks will play things safe and toss all of their perishable items if Frankestorm causes a blackout. But whether your food will actually become unsafe to eat depends on the type of food and how long the power stays out.
When it comes to food safety, not all of the food in your fridge is created equal. Foodborne pathogens need a number of conditions to thrive and multiply. The most critical factor is temperature: Food warmer than 40 degrees Fahrenheit or cooler than 140 degrees is considered to be in the danger zone, which is why keeping it refrigerated or at a constant high temperature (as at a buffet steam table, for instance) will stave off spoilage. But other factors come into play too.
Moisture content makes a big difference. Bacteria need water to survive, which is why crackers and other dry foods can safely be left in the cupboard at room temperature. Salt also poses an unfriendly environment; we cure meats, for example, by adding salt. Even pH levels are important -- think about how pickling in vinegar and brine can extend the lifespan of some food.
So even if the temperature in your fridge gets into the danger zone for longer than the critical two-hour mark, that doesn't mean the foods inside will necessarily go bad.
"Any leftovers you might have, generally if they've gotten above 40 degrees for two hours, don't even take a chance," says Cheryl Luptowski of NSF International, a food safety organization. "But butter, margarine, ketchup, canned fruits – these should be okay." The ketchup should be saved by its acidity, while salted butter in particular should be able to withstand warmer conditions.
The U.S. Department of Agriculture's food safety guide lists which food does and doesn't need to be discarded in the event of a power outage. Soft cheeses, including brie and cottage cheese, should be tossed; most hard cheeses like parmesan or cheddar, with their lower moisture content, should be fine for a while at room temperature. Ditto vinegary condiments like ketchup, relish and barbecue sauce. Other items on the list, including mayonnaise, fall in a middle ground; the USDA suggests disposing of mayo after eight hours at room temperature.
It's also worth noting that today's tightly sealed refrigerators will still keep the contents cool for a few hours without power, provided you don't keep opening the door, of course.
"Generally four hours is the max, but it depends how warm the environment is that the refrigerator is in," says Luptowski. "This time of year, the rule of thumb is if you keep the door closed it can keep a safe temperature for up to four hours."
Still, she notes that many people keep their fridges at exactly 40 degrees, which means that the temperature inside will start to reach the danger zone very soon after the power goes out. To be on the safe side, she says, turn down the temperature as low as possible before the storm hits, and keep a thermometer inside so that you can track how long the food has been in the danger zone. You can buy a little more time by putting the most at-risk items in the freezer in advance of the outage.
Speaking of the freezer, frozen food can hold out a lot longer -- up to 48 hours if the freezer is full. For the most part, the USDA advises that as long as food (including meat and vegetables) still has ice crystals and feels as cold as refrigerated food, it can be safely refreezed. Anything that has thawed and then spent more than two hours uncooked above 40 degrees should be tossed.
One more thing: If you have to evacuate, you won't know exactly how long the power's has been out in your home, especially if it's back on by the time you return. One common trick is to put a bowl of ice cubes in the freezer before you leave and check it when you get home. If you still have cubes, you know that the fridge and freezer didn't spend any significant time without power. If, on the other hand, you just have a block of solid ice, that's a sign the cubes melted and then refroze, and that you should toss anything in the fridge and freezer that's considered perishable.
And if constantly checking a thermometer and consulting food safety lists is too much to handle when you're trying to weather a major hurricane, there's only one sure way to play it safe: When in doubt, throw it out.
Matt Brownell is the consumer and retail reporter for DailyFinance. You can reach him at Matt.Brownell@teamaol.com, and follow him on Twitter at @Brownellorama.
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