Authentication of Fish Products by Large-Scale Comparison of Tandem Mass Spectra

Abstract

Authentication of food is a major concern worldwide to ensure that food products are correctly labeled in terms of which animals are actually processed for consumption. Normally authentication is based on species recognition by comparison of selected sequences of DNA or protein. We here present a new robust, proteome-wide tandem mass spectrometry method for species recognition and food product authentication. The method does not use or require any genome sequences or selection of tandem mass spectra but uses all acquired data. The experimental steps were performed in a simple, standardized workflow including protein extraction, digestion, and data analysis. First, a set of reference spectral libraries was generated using unprocessed muscle tissue from 22 different fish species. Query tandem mass spectrometry data sets from "unknown" fresh muscle tissue samples were then searched against the reference libraries. The number of matching spectra could unambiguously identify the origin of all fresh samples. A number of processed samples were also analyzed to further test the robustness and applicability of the method. The results clearly show that the method is also able to correctly identify heavily processed samples.

Overview on Untargeted Methods to Combat Food Frauds: A Focus on Fishery Products

“…More recently, Wulff et al [37] worked on the development of a new robust, proteome-wide tandem mass spectrometry method based on a simple and standardized workflow, which considers protein extraction, digestion, and data analysis for fish authenticity.…”

“…Evaluation of fish quality; discrimination of wild type from farmed fish; detection of fish mislabeling; fraudulent species substitutions; differentiation between fresh/frozen fish fillets [29][30][31][32][33][34][35] Tandem mass spectrometry Detection of seafood traceability, food safety, risk management, and authentication analysis [36,37] REIMS Identification of fish species; distinction among different catch methods within a fish species [38] MALDI-TOF-MS analysis Detection of species-specific biomarker for fish authentication; identification of fish species and substitutions; evaluation of fish freshness [39][40][41][42] Isotope ratio mass spectrometry (IRMS); stable isotopes analysis Detection of mislabeling of fish origin; discrimination of wild type from farmed fish [43,44] the assessment of authenticity of fishery products has been limited so far. In particular, SIMCA has been applied, in comparison with Linear Discriminant Analysis (LDA), to distinguish more valuable fish species, namely, red mullet and plaice, from cheaper ones (Atlantic mulled and flounder) and even to recognize Atlantic mullet fresh fillets from frozenthawed ones, starting from FT-NIR data in both cases [34].…”

Species and tissues specific differentiation of processed animal proteins in aquafeeds using proteomics tools

“…Recently methods based on the direct use of spectral libraries have been suggested [33,34] for unbiased species [20,35,36] and tissue specific [37] classification even of processed samples. To assess if such Fig.…”

“…Light microscopy methods are used to detect PAP when the feed is not supposed to contain PAP or blood products [8], and an European Union Reference Laboratory (EURL) validated polymerase chain reaction (PCR) based method [11] is used for ruminant DNA-detection [12][13][14][15] when the feed is known to contain PAP or blood products, as indicated from the declaration or the labelling [16]. While high in discriminative power for species-specific DNA fragments [17], PCR based methods suffer in accuracy when food matrices are very complex or have been processed at higher temperatures [18][19][20]. In addition, PCR does not allow for a differentiation of cellular origin [21], and hence cannot be used for tissue specific (i.e.…”

“…In most cases standard bottom-up proteomics workflows were used as means to correctly identify the samples of interest. This commonly involves gel-based or gel-free separation of proteins followed by mass spectrometric identification of proteins and peptides of interest through peptide mass fingerprinting [20]. Complementary to this, recently methods based on the direct use of spectral libraries have been suggested [33,34] that allow for unbiased species [20,35,36] and tissue specific [37] classification even of processed samples.…”