“…Generally, a food sensor converts a chemical recognition event into readable signals (e.g., electronic, , acoustic, , colorimetric , ). Compared with other types of sensors that need external devices to further transform signals to readable information, colorimetric sensors are more straightforward and convenient food quality indicators, as they are cheap, require no power, can be read by human eyes, and can be interpreted by unskilled operators such as consumers. , Recently, various colorimetric sensors have been well investigated to detect different gases, such as oxygen (O 2 ) , and carbon dioxide (CO 2 ). , For the MAP system, besides the aforementioned gases, sulfur dioxide (SO 2 ) gas is also widely used for postharvest food storage, , which could effectively prohibit the infection of gray mold and reduce the survival of foodborne pathogens in fruit and vegetables.…”