Inadequate definition of the limit of quantification used for the analysis of perfluoroalkyl substances in food by liquid chromatography-tandem mass spectrometry may compromise the reliability of the data requested by the European regulation.

Liquid chromatography-tandem mass spectrometry (LC-MS/MS) is a widespread technology used for the quantitative determination of per- and polyfluoroalkyl substances (PFAS) in foodstuff. Specifically, LC-MS/MS offers an attractive performance by combining the sensitivity and selectivity required by the European Union for testing perfluorooctane sulfonic acid, perfluorooctanoic acid, perfluorononanoic acid, and perfluorohexane sulfonic acid with maximum limits of quantification (LOQ) in the sub-parts-per-billion (µg/kg) or the parts-per-trillion (ng/kg) domains. In this article, we highlight the important diversity in LOQ definitions applied in LC-MS/MS methods described in the literature that raise concerns about the capability of some of those to generate reliable data requested by the European regulation. Here, we point out the risk of false response or misquantification if the criteria for assessing LOQ suffer from a lack of rigor. We emphasize the need to use PFAS-free samples spiked with the analyte(s) of interest and the application of identification criteria according to official documents for a sound measurement of the LOQ.

Development and in-house Validation of a Rapid LC-MS/MS Method for the Semi-quantification of Eleven Mycotoxins in Maize Samples.

The aim of this study is a current trend in chemical food safety control to increase monitoring of the co-occurrence of mycotoxins. Unsanitary conditions during harvesting, drying, packing and storage in production and processing of cereals can effect mycotoxin contamination. A method was developed for the simultaneous determination of 11 mycotoxins: deoxynivalenol, aflatoxins B1, B2, G1 and G2, ochratoxin A, fumonisins B1 and B2, zearalenone, and toxins T-2 and HT-2, allowing confirmation of their presence in maize samples as well as their identification and semi-quantification. The mycotoxins are extracted with a mixture of methanol/water, diluted with water and 0.1% formic acid and then analyzed by LC-HESI-MS/MS in a single 12 min run in positive mode. Multiple reaction monitoring mode (MRM) is applied by using two abundant fragments for each mycotoxin. Matrix effects are compensated using external matrix-matched calibration curves. Recoveries, calculated by spiking blank maize samples, ranging from 95.2% to 113.4%, were in accordance with the performance criteria required by the European Commission and intraday reproducibility ranged from 4.2% to 13.2%. Proficiency test materials and reference materials were analyzed to assess the accuracy of the method with satisfying results for the 11 mycotoxins. The method was used for monitoring of maize samples on sale in Switzerland.

An LC-MS/MS method for the quantitative determination of 57 per- and polyfluoroalkyl substances at ng/kg levels in different food matrices.

To enable the monitoring of a wide scope of per- and polyfluoroalkyl substances (PFAS) in the ng/kg level in foodstuffs, an LC-MS/MS method comprising 57 analytes was developed and validated in seven different matrices (milk powder, milk-based infant formula, meat-based baby food puree, fish and fish oil, fresh egg, and soluble coffee). The analytical approach was based on an acetonitrile:water extraction followed by solid phase extraction clean-up with subsequent quantification of the extracted analytes either by isotope dilution (55 compounds) or by standard addition (2 compounds) mass spectrometry. The validation criteria followed the guidance document for the analysis of PFAS issued by the European Union Reference Laboratory for Halogenated Persistent Organic Pollutants. The lowest limits of quantification (LOQs) for the four recently regulated compounds (L-PFOS, PFOA, PFNA, L-PFHxS) were set at 0.010 µg/kg in baby and infant foods (as sold) but also in dairy ingredients. Exception was for PFOA in milk powder due to too large variability in the repeatability. Applicability of the method was further demonstrated in 37 commodity check matrices. Overall validation data demonstrated the robustness of the method for most of the compounds and the LOQs achieved were low enough to ensure compliance with Commission Regulation EU 2022/2388 but also to support future collection of occurrence data in ng/kg level in food.

Recommendations for Oil Extraction and Refining Process to Prevent the Formation of Monochloropropane-diol Esters in Sunflower Oil.

The aim of this study was to identify the chlorine source during sunflower oil production and propose mitigation strategies in order to prevent monochloropropane-diol ester (MCPDE) formation. Whole sunflower seeds, the separated kernel, hulls, and pressed cake were studied to pinpoint the location of chlorine donors originating from the crop. Acid-water-based degumming, bleaching, cooling, and heat treatment were performed to mimic the current refining process practices. Various oil extraction and refining scenarios were tested. MCPDE and total monochloropropane-diol (MCPD) content of the heat-treated samples were determined by liquid chromatography-HRMS and by an AOCS Official method. The results show that the oil produced from crop hulls and the bleaching clay used are the strongest chlorine sources boosting the MCPDE formation. Using a mixture of pressed and solvent extracted cake oil as model, total 3-MCPD decreased by a factor of 2 when applying static cooling in combination with a washed bleaching clay.

A multi-residue pesticide determination in fatty food commodities by modified QuEChERS approach and gas chromatography-tandem mass spectrometry.

A QuEChERS (Quick, Easy, Cheap, Effective, Rugged, and Safe) based multi-residue method has been developed and validated for the extraction and determination of pesticides in fatty matrices by gas chromatography tandem mass spectrometry. Extraction and clean-up were performed according to QuEChERS principles widely used for non-fatty matrices, with main difference, a higher solvent/sample- ratio followed by a 6-fold preconcentration step, ensuring good extractability and sensitivity. A validation according to SANTE guidelines was performed using a olive and sunflower oils mixture 1:1, w/w as representative matrix, at 2 concentration levels (5 and 50 µg/kg) targeting 176 GC-amenable pesticides. Most compounds fulfilled the validation criteria, with a limit of quantification of 5 µg/kg for 137 compounds , and of 50 µg/kg for 24 compounds. Afterwards, the method performance was tested in six different fatty matrices with 73-90% of the analytes fulfilling the performance criteria at 5 µg/kg depending on the matrix.

Mitigating the formation of monochloropropanediol diesters in vegetable oils by removing their residual sediments.

This study investigates whether the formation of monochloropropane diol fatty acid esters (MCPDE) can be mitigated by removing the residual sediments from vegetable oils. Settling and centrifugation were conducted in crude sunflower and palm oil and the purified oils and their sediment-rich fractions were heated and analyzed for their MCPDE content. Increased MCPDE levels by factors of x2 to x6 were found in the sediment-rich fractions of settled sunflower oils compared to the sediment-free oil. The sediment-containing fraction could be however purified by ultracentrifugation resulting in the mitigation of MCPDE levels by a factor of 10. The effect of residual sediment on the MCPDE formation was also confirmed in the case of palm oil showing x2 to x10 more MCPDE formation in the sediment containing fractions compared to the purified oil. These results confirm that the mechanical removal of the trace sediments from crude vegetable oils results in reduced MCPDE levels.

Thermal degradation of 2-furoic acid and furfuryl alcohol as pathways in the formation of furan and 2-methylfuran in food.

This study reports the heat-induced formation of furan by decarboxylation of 2-furoic acid, and 2-methylfuran by dehydration of furfuryl alcohol under dry conditions. Model systems were incubated at temperatures up to 190 °C, followed by quantitative determination of furan and 2-methylfuran performed by isotope dilution headspace gas chromatography-mass spectrometry. Results show that 2-furoic acid decarboxylation and furfuryl alcohol dehydration are activated as from about 140-160 °C. Furfuryl alcohol and 2-furoic acids were measured in a selection of roasted coffee products by isotope dilution liquid chromatography-high resolution mass spectrometry, and the data evidenced a strong correlation between the two compounds, suggesting an intimate mechanistic relationship between them. The possible oxidation of furfuryl alcohol to furfural and 2-furoic acid in heated food is raised with particular emphasis on coffee roasting. These findings are relevant for better understanding the formation of furan and alkylfurans in food, and ultimately opening avenues for mitigation.