Early Spoilage Detection of Cultured Pacific White Shrimp Using Quartz Crystal Microbalance Gas Sensors

In this study, quartz crystal microbalance (QCM) gas sensors, coated with electrospun polyvinyl acetate (PVAc) nanofibers, were employed to monitor the spoilage level of cultured Pacific white shrimp. The sensors exhibited a sensitivity range of 0.63 to 1.61 Hz/ppm when detecting trimethylamine vapor, a key biomarker for shrimp spoilage. Significant resonance frequency shifts were observed in the as-prepared sensors when exposed to amine gases released by long-stored shrimps. These shifts underline the significance of low-temperature storage for shrimps. While color changes in the shrimps stored at ambient temperature (25 °C) become noticeable to the naked eye after 6 hours, the sensor detects sample deterioration much earlier, registering a prominent frequency shift (178 Hz) within only 3 hours of storage. This outcome suggests the potential of nanofiber-coated QCM sensors as early-stage food freshness indicators.