Advancements in Mass Spectrometry - Based Techniques for the Traceability and Safety of Cereal Products

Consumer preference in recent years has made a big shift towards organic products, while studies have shown that consumers are willing to pay premium prices for foods with traceability certification labels. Strict rules are set by European and international regulatory bodies for the labelling of such products. Nevertheless, new cases of food fraud continue to arise, constituting a threat for the economy and potentially for human health. The development of analytical techniques for the characterization of food products is imperative. Considering that cereal and cereal-based products comprise the main commodities produced and consumed worldwide, the matrices examined in this work included wheat and wheat-derived products, rice flour and gluten-free flours (oat and rice). Stable isotope ratio analysis was the primary technique applied herein for the identification of isotope markers that could distinguish between organic and conventional products, or between products grown in different geographical locations. Isotope ratio mass spectrometry (IRMS) is a potent tool, since the isotopic profiles (δ2H, δ13C, δ15N, δ18O, δ34S) of plant products reflect the plant growth environment and cultivation process. Complementary approaches were followed, namely bulk and compound-specific isotope analysis of eight amino acids (AAs), by elemental analyser (EA) -IRMS and gas chromatography - combustion (GC-C) - IRMS, respectively. Additional to the IRMS analysis for geographical authentication was the measurement of multi-elemental concentrations by inductively coupled plasma (ICP) – MS, aiding the origin assessment due to the global variation of the ‘heavy’ geoelements. The safety of the products was assessed in parallel to the organic authentication studies, specifically investigating the pesticide residue levels, as well as multi-mycotoxin contamination. Traces of synthetic pesticides have been reported in organic food products and were predominantly attributed to their presence in the environment from past use or application in the vicinity. Higher concentrations could indicate fraudulent practices. Moreover, c. 25% of global agricultural production is contaminated with mycotoxins after being naturally contaminated with fungal species, with no conclusive evidence as to the differences of occurrence between organic and conventional products. LC-MS/MS was applied for multi-mycotoxin analysis, while GC- and LC- MS/MS methods were used for the multi-residue analysis. The statistical evaluation of the results included multivariate analysis (MVA) and data fusion (DF) methods. The findings of this work contributed to the food traceability database of low-income countries, since premium Asian rice varieties, such as Jasmine and Paw San rice, were considered for the geographic assessment, suggesting reliable indicators for their authenticity. Moreover, organic authentication was achieved by CSIA for Italian rice and wheat grains, even in cases where bulk analysis was not sufficient. Lastly, higher levels of mycotoxin contamination were detected in the conventional compared to organic wheat grains, rice and oat flours. When considering the processing effects of pasta, biscuits and crackers production, pesticide contamination was found to be significantly reduced in the final products.