SIFT-MS provides instant, direct analysis of volatile freshness markers emitted from fish and seafood, ensuring that products are fresh.
Consumer acceptance and food safety are key concerns for wholesalers and retailers of fresh fish and seafood products. Although consumers provide the ultimate feedback on quality, suitable instrument-based methods can provide rapid analysis, objectivity, and low costs per sample, which are not always possible using human subjects.
Selected Ion Flow Tube Mass Spectrometry (SIFT-MS) is a very rapid, sensitive technique for assuring fish and seafood freshness. With detection limits matching those of the human olfactory system, minimal sample preparation, and direct analysis, SIFT-MS is a very effective technique for detecting spoiling of seafood early, enabling wide- scale freshness screening.
Figures 1 and 2 show the results obtained for New Zealand groper and tarakihi. In both cases, the concentration of trimethylamine, a compound with the characteristically “fishy” aroma of spoilage, increases significantly through the testing period. Ammonia, various sulfur compounds, and oxygenates are also detected in the early stages of spoilage and increase as the samples age. Ethyl propionate, which is detected only in tarakihi, begins to decrease at six hours.
Mussels exhibit a very different headspace composition as they age (Figure 3). Their headspace is dominated by dimethyl sulfide, even at the initial measurement. A number of other major and minor components are also observed (Figures 3a and 3b), including trimethylamine. Ammonia exhibits unusual behavior in this instance, because the concentration decreases monotonically with increasing sample age.
This study demonstrates that SIFT-MS is extremely well suited to early detection of fish and seafood spoilage. The Syft Voice200ultra SIFT-MS instrument provides a robust, easy to operate solution for sensitive, quantitative screening of large numbers of samples per day, both manually and automatically (via autosampler integration).