Truffles represent the best known and most expensive edible mushroom. Known as Ascomycetes, they belong to the genus Tuber and live in symbiosis with plant host roots. Due to their extraordinary taste and smell, truffles are sold worldwide for high prices of up to 3000–5000 euros per kilogram (Tuber magnatum PICO). Amongst black truffles, the species Tuber melanosporum VITTAD. is highly regarded for its organoleptic properties. Nonetheless, numerous different sorts of black truffle are offered at lower prices, including Tuber aestivum VITTAD., Tuber indicum and Tuber uncinatum, which represent the most frequently consumed types. Because truffles do not differ visually for inexperienced consumers, food fraud is likely to occur. In particular, for the highly prized Tuber melanosporum, which morphologically forms very similar fruiting bodies to those of Tuber indicum, there is a risk of fraud via imported truffles from Asia. In this study, 126 truffle samples belonging to the four mentioned species were investigated by four different NIR instruments, including three miniaturized devices—the Tellspec Enterprise Sensor, the VIAVI solutions MicroNIR 1700 and the Consumer Physics SCiO—working on different technical principles. Three different types of measurement techniques were applied for all instruments (outer shell, rotational device and fruiting body) in order to identify the best results for classification and quality assurance in a non-destructive manner. Results provided differentiation with an accuracy up to 100% for the expensive Tuber melanosporum from Tuber indicum. Classification between Tuber melanosporum, Tuber indicum, Tuber aestivum and Tuber uncinatum could also be achieved with success of 100%. In addition, quality monitoring including discrimination between fresh and frozen/thawed, and prediction of the approximate date of harvesting, was performed. Furthermore, feasibility studies according to the geographical origin of the truffle were attempted. The presented work compares the performance for prediction and quality monitoring of portable vs. benchtop NIR devices and applied measurement techniques in order to be able to present a suitable, accurate, fast, non-destructive and reliable method for consumers.

This work is the first to describe the use of Direct Analysis in Real Time mass spectrometry (DART-MS) for the rapid and cost-effective quality control of cigars. Multivariate analyses (PCA and LDA) on mass spectra led to highly efficient models for the discrimination of tobacco products. In addition to the geographic origin of the cigars, different pretreatments of the tobacco leaves could also be determined. Cross-validations of the models yielded prediction accuracies up to 92.18%. All results were compared using LC-MS as reference method. Multivariate analyses of chromatograms also yielded powerful models with correctness scores up to 88.1%. However, the models generated with LC-MS were neither able to determine the geographic origin of the tobacco leaves nor different pretreatments. In addition to qualitative analysis, the nicotine content of tobacco leaves was also determined via both methods. While precise quantification was not possible with DART-MS, a correlation coefficient of >0.96 was achieved in direct comparison with LC-MS, which allows semi-quantitative statements about the nicotine content without any problems.

This work is the first to describe the use of Direct Analysis in Real Time Mass Spectrometry (DART-MS) for the rapid quantification of cannabidiol (CBD) in CBD oils.

Shiga toxins (Stxs), especially the Stx2a subtype, are the major virulence factors involved in enterohemorrhagic Escherichia coli (EHEC)-associated hemolytic uremic syndrome (eHUS), a life-threatening disease causing acute kidney injury, especially in children. After oral transmission and colonization in the gut, EHEC release Stx. Intracellular cleavage of the Stx A subunit, when followed by reduction, boosts the enzymatic activity that causes damage to targeted cells. This cleavage was assumed to be mostly mediated by furin during Stx intracellular trafficking. To investigate whether this cleavage could occur in the intestine, even prior to entering target cells, Stx2a A subunit structure (intact or cleaved) was characterized after its exposure to specific host factors present in human stool. The molecular weight of Stx2a A subunit/fragments was determined by immunoblotting after electrophoretic separation under reducing conditions. In this study, it was demonstrated that Stx2a is cleaved by certain human stool components. Trypsin and chymotrypsin-like elastase 3B (CELA3B), two serine proteases, were identified as potential candidates that can trigger the extracellular cleavage of Stx2a A subunit directly after its secretion by EHEC in the gut. Whether the observed cleavage indeed translates to natural infections and plays a role in eHUS pathogenesis has yet to be determined. If so, it seems likely that a host’s protease profile could affect disease development by changing the toxin’s biological features.

Shiga toxins (Stxs), and more specifically the Stx2a subtype, are the major virulence factors involved in enterohemorrhagic Escherichia coli (EHEC)-associated hemolytic uremic syndrome (eHUS); a life-threatening disease causing acute kidney injury, especially in children. Cleavage of Stxs A subunit, when followed by reduction, boosts the enzymatic activity causing damage to targeted cells. This cleavage was assumed to be mostly mediated by furin during Stx intracellular trafficking. Cleavage of A subunit, without reduction, changes the binding properties of Stxs for blood components during HUS pathogenesis. To investigate whether the cleavage could occur in the intestine, even prior entering target cells, Stx2a structure was characterized after its exposure to specific host factors present in human stool. The structure of Stx2a A subunit was determined by immunoblotting after electrophoretic separation under reducing conditions. Trypsin and chymotrypsin-like elastase 3B (CELA3B), two serine proteases, were identified as potential candidates that may trigger the extracellular cleavage of Stx2a A subunit directly after its secretion by EHEC in the gut. Whether this observation indeed translates to natural infections and plays a role in eHUS pathogenesis has yet to be determined as well as whether host's protease profile could affect disease development by changing the toxin’s biological features.