Combined wire services Keep 'em safe: The U.S. Department of Agriculture lists these basic guidelines for safely packing school lunches:

"Since food poisoning bacteria grow best at room temperature, meat and poultry should not be out of the refrigerator longer than two hours."Remember these rules: Keep cold foods fully cold (try a small ice pack). Keep hot foods completely hot (use a thermos). Keep everything clean.

Wash lunch containers in hot soapy water, then rinse and dry. Do not reuse paper bags; spilled liquid or food particles can breed bacteria.

More questions about lunch boxes or safe cooking in general? Call USDA's toll-free Meat and Poultry Safety Hot Line at 800-535-4555 between 10 a.m. and 4 p.m. Monday-Friday.