Kiera Butler

Kiera Butler

Senior Editor

A senior editor at Mother Jones, Kiera covers health, food, and the environment. She is the author of the new book Raise: What 4-H Teaches 7 Million Kids—and How Its Lessons Could Change Food and Farming Forever (University of California Press).

 

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Can You Unplug Your Fridge at Night To Save Money and Energy?

| Mon Dec. 13, 2010 5:30 AM EST

This interesting question from Econundrums reader Myk recently caught my attention:

I have often wondered if it would be possible to unplug my fridge at night when I know for certain that no one will need to open it for eight hours. Would the unit keep in the cold if the doors remained closed?

The short answer is no, says LeeAnne Jackson, health science policy advisor at FDA's Center for Food Safety and Applied Nutrition. "Refrigerators should be maintained at a constant temperature setting at 40 degrees Fahrenheit or below," writes Jackson in an email. "Numerous foods in your refrigerator might have bacteria on them, and the cold temperature inhibits the bacteria from multiplying (or at least slows it down). If the food warms up, the bacteria will reach harmful levels faster." For this reason, the USDA recommends that food left in an unplugged, unopened fridge for more than four hours be tossed. (Frozen items left in a full freezer stay good for two days; in a half full freezer it's more like 24 hours.)

And even if you're willing to risk spoiling your food (or you only keep in your fridge food that can withstand higher temperatures), the energy savings aren't significant, since "if the refrigerator is unplugged more energy will be used to cool the refrigerator back down to 40 degrees Fahrenheit than if the refrigerator simply maintains the temperature at 40 degrees," says Jackson.

Bruce Nordman, an energy efficiency researcher at the Lawrence Berkeley National Laboratory, basically agrees with Jackson. "You do use energy to go back to the original temperature, but should save some with the higher temperature," he says. "However, the savings are strictly proportional to the amount of time at the higher average temperature, so you only save a lot if the temperature goes way up." Which, of course, you wouldn't want it to, given the bacteria problem.

Want to save energy in your fridge? Here are six top tips for maximizing the efficiency of your refrigerator, from the American Council for an Energy-Efficient Economy.

Got a burning eco-quandary? Submit it to econundrums@motherjones.com. Get all your green questions answered by visiting Econundrums on Facebook here.

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Mercury Tuna: Are the FDA's Recommendations Too High?

| Tue Dec. 7, 2010 6:30 AM EST

From the department of #butilovetunamelts comes this depressing news: The Consumers Union recently analyzed 42 samples of packaged tuna, and found that about half a can of white (albacore) tuna (which tends to have more mercury than light tuna) contains more mercury than the EPA's recommended daily limit for women of childbearing age. A few other nuggets from the study:

  • Every sample contained measurable levels of mercury, ranging from 0.018 to 0.774 parts per million. The FDA can take legal action to pull products containing 1 ppm or more from the market.  (It never has, according to an FDA spokesman.)
  • Samples of light tuna had 0.018 to 0.176 ppm and averaged 0.071 ppm. At that average, a woman of childbearing age eating 2.5 ounces would get less than the EPA’s limit, but for about half the tested samples, eating 5 ounces (about one can) would exceed the limit.

Given the fact that mercury content varies dramatically from can to can, Consumers Union recommended in 2006 that the FDA issue a warning that some cans of white tuna may contain levels that exceed those on which the daily consumption recommendations are based. The agency hasn't issued any such warning yet.

In light of its recent tests, Consumers Union recommends that tuna-eaters adopt a more cautious approach than the FDA recommends:

Children less than 45 pounds: 0-4 ounces of light tuna or 0-1.5 ounces of white (albacore) tuna per week, depending on the child's  weight.
Children 45 pounds or more: About 4 to 12.5 ounces of light tuna or 1.5 to 4 ounces of white tuna per week, depending on the child’s weight.
Pregnant women: To be careful, avoid canned tuna. Choose a low-mercury fish instead.
Women of childbearing age: About 12.5 ounces of light tuna or 4 ounces of white tuna per week.
Men and older women: About 14.5 ounces of light tuna or about 5 ounces of white tuna per week should be OK, but people who eat fish more often would be prudent to stick to low-mercury types.

(For comparison, the FDA's recommended limit for low-mercury seafood, including light tuna, is 12 ounces a week. For white tuna, it's six ounces a week.)

Also worth noting: Bluefin tuna is not only one of the most mercury-laden kinds of tuna, it's also one of the world's most overfished sea creatures. A recent bad decision on 2011's bluefin tuna quotas means this struggling fish is now even worse off.

Wondering which fish are healthy for you and the planet? I like Food and Water Watch's Smart Seafood Guide.

Got a burning eco-quandary? Submit it to econundrums@motherjones.com. Get all your green questions answered by visiting Econundrums on Facebook here.

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