Revell advised against the old-fashioned sniff test, especially with cooked food. "There are all kinds of harmful bacteria and toxins you can't smell. You can't rely on your nose to tell you."
Once foods have been sitting around more than 2 hours, "it's not worth trying to eat them again. Throw them out; they're dangerous," Revell said. "It's painful to throw out food, but it's even more painful to have food illness or food poisoning over the holidays."
You can take it from my mother, Doris J. Allen, whose simple rule in our family's New Jersey home applies equally well to clearing a cluttered room or a refrigerator chock full of carefully wrapped leftovers: "When in doubt, throw it out."
The USDA Meat and Poultry Hotline, 1-888-674-6854, fields 80,000 calls a year with questions about the storage, handling and preparation of meats, poultry and eggs.
StillTasty.com provides specifics for thousands of foods about how long they're edible before they should be tossed out.
The Partnership for Food Safety Education,including representatives of the USDA, FDA and CDC created a joint campaign with advice on how to safely handle and cook many types of food.
FoodSafety.gov is a gateway site for federal food safety information.