Despite the use of expiry dates on certain foods, it can still be hard to tell when something has truly gone bad; however, the use of edible silk sensors can change all of that. Similar to stickers found on fruit and vegetables, these sensors are stuck onto various types of food and can even be plopped into cartons of milk. They will indicate whether or not the food they’re placed in is safe to eat or drink.
Developed by scientists at the Tufts University, the edible silk sensors are made out of a gold antennae embedded in a purified silk film. The gold bits are comparable to the slivers often used in luxurious desserts while the silk substrate is pure protein. When the food begins to rot, the edible silk sensors start to emit a different electromagnetic signal, which can be read by smartphones.