If you like to travel and store food in the freezer, make sure you’re not putting your health in danger by eating expired or spoiled food. If the power goes out while you’re away, the frozen food may defrost, resulting in spoilage.

Fortunately, a woman has devised an ingenious method for ensuring that our refrigerators operate at peak efficiency with only a mug of water and a penny.

If you follow this simple tip, you no longer have to worry about eating expired or ruined vegetables from the freezer.

It’s worth noting that if the power goes out, the water in the mug will freeze alongside the food in the freezer. When the electricity is restored, the penny will be moved to a new location on top of the ice.

This activity indicates that the food in the freezer is still fresh and safe to consume.