A High-Performance Artificial Olfactory Chip for Real-Time Cold Chain Food Freshness Monitoring

Intelligent food freshness monitoring systems are in urgent demand for food safety and quality assurance in modern cold chain transportation. Conventional monitoring techniques are rendered impractical within the hermetic confines of refrigeration units. Conversely, the utilization of electronic olfactory systems to discern distinct volatile molecules emitted by food stored during the deterioration process presents an effective monitoring remedy. In this study, an artificial olfactory chip featuring a nine-box-grid configured gas sensor array (9-Array) has been designed for smart cold chain management. Through its nanotubular design, the 9-Array chip exhibits remarkable sensitivity and discriminability to ammonia (NH 3 ), ethanol (EtOH), trimethylamine (TMA), and hydrogen sulfide (H 2 S) emitted from decaying meat, vegetables, and fruits. Notably, this chip excels in accurately categorizing these gases and their combinations by leveraging distinct responses from individual sensor pixels, enabling the precise differentiation of overlapping gas signatures originating from diverse food sources. When seamlessly integrated into a food freshness monitoring system within a refrigerated environment, the 9-Array chip showcases reliable real-time monitoring capabilities and sustained performance over extended periods. It possesses the capability to recognize at least 7 types of foods and evaluate their freshness over 7 days. Moreover, our olfactory chip adeptly identifies and evaluates the freshness of varied food items within mixed food contexts, showing its potential as a future key component for advanced smart cold chain food management platforms that elevate food management efficiency and safety standards.