The food spoilage detector is an instrument that can be placed in a room and can test food freshness within a certain space (50 square meters), including food stored in the refrigerator or cupboard. It can be connected to a display device, for example, on the wall surface, providing accurate expiration dates for various foods. Different indicator lights show different levels of freshness. Recommendations for daily healthy recipes are also shown on the screen. The detector analyses the freshness of the food by detecting molecules released by food, such as fish, meat or fruit when they start to degrade (e.g. ethylene from fruit, amines from fish). This can effectively reduce the amount of food waste. And it prevents people from getting sick from eating bad food. Besides, the fermentation of food by microorganisms will release a large amount of greenhouse gases and other harmful substances.