ABSTRACT Because the world's wild fish stocks are limited and the market demand is increasing, fish farming has become an alternative food source and a way to reduce costs for consumers. The sale of farmed as wild fish is a fraudulent practice; it is, therefore, important to find new and alternative tools that can help in the fight against fraud to protect consumers and to ensure food traceability. The proteomic profiles of farmed and wild fish differ. With this study we wanted to identify liver protein markers via two-dimensional electrophoresis that would allow us to distinguish wild from farmed gilthead seabream. The liver samples from 32 gilthead seabream, wild and farmed, were stored at −80°C before protein extraction. The samples were subjected to two-dimensional electrophoresis to detect qualitative and quantitative differences. Proteomic analysis showed a protein spot (molecular weight of ∼34 kDa and isoelectric point of ∼6.9) only in the samples from the wild gilthead seabream; liquid chromatography–tandem mass spectrometry identified the spot as ubiquitin. Ubiquitin could be a valid marker to differentiate wild from farmed gilthead seabream; it could be used to ensure continuous monitoring throughout the entire commercial chain and to fight commercial fraud. HIGHLIGHTS A proteomic approach to differentiate the method of fish production is proposed. A 2-DE spot, characterized by MS/MS as ubiquitin, differentiated between samples. Liver proteome could be useful to find biological markers.

ABSTRACT A simple method based on direct sampling analysis, coupled with a time of flight mass spectrometer, was developed to discriminate between wild and farmed sea bream on the basis of the docosahexaenoic and arachidonic fatty acid ratio. Good precision in repeatability and reproducibility (relative standard deviation < 15%) was obtained. The fatty acid ratios of the two types of fish were statistically significant (Student's t < 0.001). The use of a simple, rapid, and cost-effective tool could aid in the detection of commercial fish fraud, increase the number of controlled samples, and strengthen control along the entire commercial chain. HIGHLIGHTS The sale of farmed fish as wild fish is a common fraudulent practice. A rapid method was validated to discriminate between wild and farmed sea bream. The DHA/AA ratio between fatty acids allows differentiation of farmed from wild sea bream.

ABSTRACT Sudan dyes are synthetic azo dyes used by industry in a variety of applications. Classified as carcinogenic, they are not allowed in foodstuffs; however, their presence as adulterants in food products has been regularly reported. Here, we describe an innovative screening method to detect Sudan I, II, III, and IV in tomato sauce, palm oil, and chilli powder. The method entails minimal sample preparation, completely avoiding the liquid chromatography phase, followed by detection and identification through atmospheric pressure chemical ionization time-of-flight mass spectrometry, in positive ionization mode. Analytes were efficiently identified and detected in samples, fortified both with individual analytes and with their mixture, with an error in mass identification less than 5 ppm. Limits of identification of the analytes in the fortified samples were 0.5 to 1 mg/kg, depending on the dye and matrix. The method had a linear range of 0.05 to 5 mg/kg and good linear relationships ( R 2 > 0.98). Repeatability was satisfactory, with a coefficient of variation lower than 20%. The method was applied to detect the dyes in real adulterated chilli samples, previously found positive by confirmatory high-performance liquid chromatography–mass spectrometry and ELISA, and in commercial products purchased from supermarkets. In all positive samples, analytes were correctly identified with an error in mass identification lower than 5 ppm, while none of the 45 commercial samples analyzed were found to be contaminated. The proposed new assay is sensitive, with a limit of identification, for all the three matrices, complying with the limits defined by the European Union (0.5 to 1 mg/kg) for analytical methods. Compared with conventional methods, the new assay is rapid and inexpensive and characterized by a high throughput; thus, it could be suitable as screening technique to identify Sudan dyes in adulterated food products.