A thermometer tells what's happening inside your refrigerator

One of the best purchases for your kitchen is a refrigerator thermometer. It's a good check on those temperatures that are so crucial for proper food storage. And though the dial on the inside of the fridge may say one thing, you still need to double-check its accuracy.

The best temperature for foods is a range between 34 and 40 degrees, according to Jackie Newgent, author of "Big Green Cookbook." But, she writes, "I keep my fridge set at 39 degrees — there is no need to go much lower than that" to keep food from spoiling. The freezer temperature should register 0 degrees.

Newgent also notes that appliances account for about 20 percent of a typical household's energy use. "The refrigerator is the biggest energy glutton in most household kitchens," she writes.

A few steps can reduce your refrigerator energy use:

Don't stand in front of the refrigerator with the door open, trying to make a decision.

Keep it nicely stocked, but not overstocked, for best energy efficiency.

Look for refrigerator thermometers at department stores and cookware shops. Prices range from $7 to $23.

How long should you store foods in the fridge? Go to the federal government site foodsafety.govto find freezer and refrigerator storage times for many types of foods.