Rapid control of smoked Atlantic salmon ( Salmo salar) quality by electronic nose: Correlation with classical evaluation methods

Abstract

A prototype solid-state-based gas-sensor array system including a gas sampling unit, the FishNose, for direct quality measurements of smoked salmon has been developed. Quality changes of smoked salmon during storage were monitored by the FishNose and compared with the results of traditional sensory, chemical, and microbial measurements. Gas-sensor selection was optimized for the detection of changes in the very volatile compounds mainly representing microbial metabolism during spoilage. Sensor readings of repeated measurements of calibration samples showed a repeatability for the six sensors of the array of 6.4% (±1.4%), and for repeated measurements of fish samples the repeatability was 4.3% (±2.6%) without purge of the system between the measurements. The system was further tested on-site in a smoked salmon production plant. Due to varying ambient air conditions at the production plant during the measurements, the sensor readings had to be corrected for by subtracting the sensor readings for the background air. High classification rates were obtained of 95 and 93% for good and bad samples, respectively. This work demonstrated that the FishNose, equipped with an application specific sampling unit, was suitable for monitoring quality changes occurring during storage of smoked salmon and that the system was able to predict the quality related attributes like sweet/sour and off odour, and microbial counts.