Fish freshness sensor

An array of semiconducting metal oxide (SMO) chemiresistive sensors can quantitatively measure the freshness of Atlantic salmon (Salmo salar). A variety of SMO films were tested, including films containing oxides of tungsten and tin. Experiments were performed with these films to determine if they were sensitive to trimethylamine (TMA) and/or dimethylamine (DMA), known Atlantic salmon degradation products. The electrical resistance of the films before and during exposures to concentrations of the amines was monitored. The sensor temperatures were varied to determine the operating conditions for sensitivity and selectivity to one or both gases. The most promising films were then used to monitor the degradation of Atlantic salmon in conjunction with a sensory evaluation panel and tests using gas chromatography mass spectrometry (GCMS) and total volatile base nitrogen (TVBN).