The food spoilage detector is an instrument that can be placed in a room and can detect food within a certain space (50 square meters), including food stored in the refrigerator or cupboard. And it can be connected to a display device, for example, on the wall surface, providing accurate expiration dates for various foods and recommendations for healthy recipes. The detector judges the freshness of the food by molecules in the air, molecules are emitted from foods such as fish, meat or fruit when they start to degrade (e.g. ethylene from fruit, amines from fish). This can effectively reduce the phenomenon of food waste. What is wasted by people is not only the food itself that can save people from hunger, but also the natural resources used to produce them. Besides, the fermentation of food by microorganisms will release a large number of greenhouse gases and other harmful substances.