Is Your Milk Spoiled? Find Out With Smart Tag

The traditional way of discovering if your gallon of milk has gone bad is by smelling it, or by accidentally drinking it only to find out it has spoiled. However, you may not have to do either of these in order to discover the status of your dairy drink. Scientists in China have come up with a new way to tell if your milk is good or bad: the smart tag.

What is a smart tag?
Smart tags are small gel-based tabs that are put onto containers of food and drinks. When the food has spoiled or gone bad, the sticker changes color to indicate that change. One factor that affects how these tags work is temperature. The stickers react to changes in temperature, which can have an impact on the freshness of a certain product. The tag is made up of tiny particles of metal, also known as metallic nanorods. Also embedded in the sticker are vitamin C, acetic and lactic acids, and agar.

The meaning of color
The color your sticker changes can indicate a number of things about your food or drink. It starts out red, then can change to different shades. Red means the food is fresh and OK to eat or drink. Green, however, means the product is better off in the trash. Your milk or food item may turn orange or yellow as well, which can indicate that its still good to eat, but could be expired sooner rather than later. Dr. Chao Zhang, a scientist at Peking University in Beijing, explained that when a tag goes from red to orange, this suggests that there’s only about seven days left in the life of that particular product.

Students of cooking school online can use the smart tag to ensure they’re using only the freshest ingredients in their culinary creations, but experts are aiming to tailor these stickers to be used for more than just food and drinks. They’re hoping they can be adapted to work for a variety of substances, including medicine.