"For the most part the containers just couldn't keep foods hot or cold enough for them to remain safe from the time the child would leave the house in the morning until they would eat lunch," says Sharon Franke, Kitchen Appliances Director at the Good Housekeeping Research Institute.
Two thermos' containers did do very well, though. The $15 Funtainer Food Jar can store hot foods safely for up to six hours and its squat design makes it perfect for stews, stir-fries, pastas and soups.
But, be careful with cold food, it's only safe for up to four hours. Another find is the $35 Sigg Thermo Bottle Fashion Line, it's too large to send along with young children, but could work well with a sporty teen who drinks throughout the day.
Remember that some containers are only suitable for exclusively hot or exclusively cold foods, so check the labels carefully.
Because 'safe' hot temperatures of 140ºF or above are hot enough to scald small children, only children with the dexterity to pour carefully and judgment to know how to handle spills should be allowed to carry and use thermal containers filled with hot liquid.