Precision and Application of Electronic Nose for Freshness Monitoring of Whole Redfish (Sebastes marinus) Stored in Ice and Modified Atmosphere Bulk Storage

An electronic nose with electrochemical gas sensors (CO, NH3, SO2 and H2S) was used as a rapid technique to monitor changes in the headspace of whole ungutted redfish (Sebastes marinus) stored in ice and under various conditions of modified atmosphere (MA) bulk storage (CO2/N2:60/40). The precision of the electronic nose measurements was determined using standard compounds (ethanol, trimethylamine, acetal-dehyde and dimethyldisulfide). The response of the CO sensor, suggesting the formation of alcohols and carbonyls, increased with time for both aerobic and MA storage and correlated well with sensory analysis using the Quality Index Method. Slower spoilage rate reflected by lower intensities of sensors' responses, lower microbial counts and less TMA production were observed in MA-stored redfish compared with aerobic storage in ice.