Biotransformation of diclofenac by Stenotrophomonas humi strain DIC_5 and toxicological examination of the resulting metabolites.

The widely used non-steroidal anti-inflammatory drug, diclofenac, detected in increasing concentrations in freshwater ecosystems, is among the most pressing environmental problems today. In this study, the bacterial isolate Stenotrophomonas humi strain DIC_5 was capable of degrading diclofenac. It eliminated 75.1% of diclofenac at an initial concentration of 1.5 mg/L after 8 days in the presence of glucose (3.0 g/L). During the process, nitro-diclofenac was identified as a resulting metabolite, whose concentration increased significantly in the bacterial medium from the 7th day of the experiment, while the concentration of diclofenac decreased correspondingly. The ecotoxicological tests on Aliivibrio fischeri and zebrafish embryos showed that the bacterial metabolites without diclofenac have a higher toxicity (up to 35.5% bacterial bioluminescence inhibition and 36.7% embryo mortality) than the diclofenac degradation residues (28% and 26.7%, respectively). Based on these results, neither diclofenac nor its degradation products exhibit toxic effects on the test organisms. Conversely, the toxic effect caused by the bacteria was reduced in the presence of diclofenac. Our work highlights the importance of using biotic controls in biotransformation trials, especially when the foreign material is applied in intermediate or environmentally relevant concentration ranges. KEY POINTS: • Biotransformation of diclofenac by bacteria isolated from a bacterial biofilm. • Biotransformation of diclofenac led to the formation of nitro-diclofenac. • Microorganisms are alternatives for reducing the concentration of diclofenac in water.

Underexplored food safety hazards of beekeeping products: Key knowledge gaps and suggestions for future research.

These days, a growing consumer demand and scientific interest can be observed for nutraceuticals of natural origin, including apiculture products. Due to the growing emphasis on environmental protection, extensive research has been conducted on the pesticide and heavy metal contamination of bee products; however, less attention is devoted on other food safety aspects. In our review, scientific information on the less-researched food safety hazards of honey, bee bread, royal jelly, propolis, and beeswax are summarized. Bee products originating from certain plants may inherently contain phytotoxins, like pyrrolizidine alkaloids, tropane alkaloids, matrine alkaloids, grayanotoxins, gelsemium alkaloids, or tutin. Several case studies evidence that bee products can induce allergic responses to sensitive individuals, varying from mild to severe symptoms, including the potentially lethal anaphylaxis. Exposure to high temperature or long storage may lead to the formation of the potentially toxic 5-hydroxymethylfurfural. Persistent organic pollutants, radionuclides, and microplastics can potentially be transferred to bee products from contaminated environmental sources. And lastly, inappropriate beekeeping practices can lead to the contamination of beekeeping products with harmful microorganisms and mycotoxins. Our review demonstrates the necessity of applying good beekeeping practices in order to protect honeybees and consumers of their products. An important aim of our work is to identify key knowledge gaps regarding the food safety of apiculture products.

Lipophilized rosmarinic acid: Impact of alkyl type and food matrix on antioxidant activity, and optimized enzymatic production.

In this study, the initial focus was on exploring the simultaneous impact of the oil-based food matrix and the polarity of rosmarinic acid derivatives on the antioxidant properties. Rosmarinic acid (RA) showed remarkable DPPH, FRAP, and ABTS radical scavenging activities, followed by methyl rosmarinate (MR) and ethyl rosmarinate (ER). In bulk oil, both conjugated dienes and p-AnV values reached a peak in the following order after 30 days: ER > MR > RA = BHT > control (no antioxidant). In the oil structured using monoacylglycerol, MR was more effective than ER and RA. For ethyl cellulose oleogel, emulsion, and gelled emulsion systems, RA was more effective. Additionally, after confirming the importance of the food matrix on the antioxidant activity of RA derivatives, the lipophilization of RA with ethanol was optimized as a model with Lipozyme 435 in hexane. A conversion yield of as high as 85.59% for ER was achieved, as quantified by HPLC-UV and confirmed by HPLC-DAD-ESI-qTOFMS.

Accumulation of HT-2 toxin from contaminated mushroom compost by edible Agaricus bisporus.

Wheat straw is commonly used as a cellulose source in mushroom compost and could be a secondary source of mycotoxin contamination in the food chain. We cultivated edible Agaricus bisporus and Pleurotus ostreatus on T-2/HT-2 artificially-contaminated mushroom compost and developed and in-house validated an UHPLC-MS/MS method for determination of T-2, HT-2, T2-triol and T2-tetraol in mushroom compost and mushroom basidiocarp. A rapid phase I metabolization of T-2 and HT-2 in mushroom compost was observed. In Agaricus bisporus, basidiocarps 8-15 µg kg-1 accumulation of HT-2 calculated on wet weight was measured. No detectable mycotoxins were found in Pleurotus ostreatus basidiocarp.

Determination of Pesticides in Bee Pollen: Validation of a Multiresidue High-Performance Liquid Chromatography-Mass Spectrometry/Mass Spectrometry Method and Testing Pollen Samples of Selected Botanical Origin.

Pollen is a source of nutrients for honeybees (Apis mellifera L.) and suitable for human consumption as well. In our research, a multiresidue method for pesticide determination was developed and validated for the bee pollen matrix. 247 components met the validation criteria for limit of detection, limit of quantification, linearity, and interday repeatability. Average recoveries varied between 70 and 120% except for 14 analytes, which were corrected during on-going validation. The matrix effect was strong for certain analytes, which required the use of matrix-matched calibration. The pesticide residue profiles of 21 pollen samples of different botanical origins were identified by the developed method. The most common active substances were chlorpyrifos, thiacloprid, and acetamiprid. Some products contained pesticides that are already banned. According to our estimates, the tested samples do not pose an acute risk on honeybees, although the combination of pesticides may cause synergistic toxicity.

Development of analytical protocol for the investigation of transformation products of pre-harvest fungicides in fruits using LC-MS/MS methods.

Chemical protection of plants is critical to permit all-year-long availability of plant products. These chemical agents are transformed both biotically and abiotically after spraying. Our purpose was to develop a workflow which is suitable to investigate those transformation products from plant matrices. Two field trials were set up in two years in two different plant matrices (apples, cherries) to develop a workflow to map the transformation products (TP) of three selected pre-harvest fungicides (boscalid, fluopyram, pyraclostrobin) in the fruits. Modified QuEChERS extraction method was applied for the extraction of TPs from the fruit matrices. We used liquid chromatograph-mass spectrometers to identify and confirm the transformation products of fungicides. LC-QTOF-MS method was suitable to map the key fragmentation routes of parent fungicides. Based on fragmentation pathways, MRM (multiple-reaction monitoring) transitions of fungicide-metabolites mentioned in the literature were predicted. HPLC-QTRAP-MS in target mode was successfully applied to monitor trace level of metabolites and in some cases their isomers. For confirmation of the identified metabolites, LC-QTOF-MS was used. Five earlier-documented as well as one novel transformation product (deschloro-FLP) were found in the investigated fruit samples, the latter has not been reported in plant matrices so far. Area-normalisation method was used to follow the relative concentration of the transformation products in the fruits as a function of time.

Comparison of QuEChERS and "dilute and shoot" extraction methods for multi-mycotoxin analysis of samples from button mushroom (Agaricus bisporus) cultivation.

Several components of mushroom compost (wheat straw, chicken manure) can be contaminated with mycotoxins posing food health risks to mushroom consumers. To assess the relevance of such contaminations high-throughput analytical methods are needed. In this study, two sample preparation approaches, dilute & shoot (D&S) and modified citrate buffered Quick, Easy, Cheap, Effective, Rugged, Safe (QuEChERS) were compared in terms of extraction efficiency and matrix effect in case of 13 mycotoxins in complex matrices-wheat straw, the growing media and button mushrooms (Agaricus bisporus)-of mushroom cultivation using high-performance liquid chromatography tandem mass spectrometry (HPLC-MS/MS). D&S method resulted in recoveries of LB medium, button mushroom and compost for ≥60% in case of all investigated mycotoxins except for DON-3G. However, using modified citrate buffered QuEChERS with 2% acidification of the extraction solvent showed the complete loss of strongly polar DON-3G and fumonisin B1 (FB1). The investigated matrices had suppressive effect on ionization in all target mycotoxins except for FB1. Regarding the use of isotopologues to compensate matrix effect, even U-[13C15]-DON and U-[13C24]-T-2 can also be used to quantify their related metabolites in the studied matrices, using internal standard method.

Multi-mycotoxin LC-MS/MS method validation and its application to fifty-four wheat flours in Hungary.

In this study, fifty-four wheat flour and wheat-based products available on the Hungarian market were assessed for twelve mycotoxins. Prior to analysis, a multi-mycotoxin method using high-performance liquid chromatography coupled with tandem mass spectrometry (HPLC-MS/MS) was developed and validated for wheat and wheat-based products. A simple extraction with acetonitrile/water/formic acid (79/20/1 v/v%) was used for sample preparation. The limits of quantitation (LOQ) were between 0.02 and 161 µg kg-1. Good linearity (r2 > 0.995) was achieved for all mycotoxins investigated. Recoveries varied between 88 and 120% at three concentration levels. Based on the low relative matrix effect (RSD < 0.15%) of the different wheat flour samples, matrix-matched calibration was used, which also proved its suitability in proficiency testing (z-scores: -0.6 for DON; +1.5 for OTA; -0.5 for ZEA). DON was the predominant mycotoxin, which contaminated 84% of the investigated samples. Metabolised forms of DON were found in spelt, durum flour and some wheat-based products (D3G in 4 samples, 15Ac-DON in 7 samples). T-2 and HT-2 were the second most frequently detected mycotoxins. All investigated samples complied with current European/Hungarian legislation.

Thio arsenosugars identified as natural constituents of mussels by liquid chromatography-mass spectrometry.

Two novel thio arsenosugars have been identified by liquid chromatography-mass spectrometry as significant arsenic constituents in samples of mussels.

The potential of arsenic speciation in molluscs for environmental monitoring.

This paper reports the assessment of total arsenic and six arsenic species (As(III), As(V), MMA, DMA, AsBet, AsCol) as contaminants of mussel samples collected around the island of Sardinia and in the Gulf of Venice. The samples were analysed using cation- and anion-exchange HPLC-HG-AFS for speciation and ICP-AES for the total As determination. To ensure the robustness of the routine analytical method, the technique was validated using a candidate reference material, BCR-710, and good agreement was obtained. It was recognised that higher total arsenic concentration in mussels does not necessarily result in higher toxicity of mussel samples.

Preparation, homogeneity and stability studies of a candidate LRM for Se speciation.

A laboratory reference material (LRM) was prepared from Brazil nuts (Bertholletia excelsa) for quality control (QC) purposes of selenium speciation. The preparation of this LRM led through the usual operation steps applied during routine reference material production from biota samples-preparation of the raw material, homogenisation, storage design, checking of homogeneity, microbiological status and possible irradiation effects, and monitoring the species stability vs time at different storage temperatures. The selenium speciation studies to check species stability were carried out on a HPLC-UV-HG-AFS measurement set-up. Special attention was paid to the correct identification of selenium species by applying independent HPLC separation techniques (ion-pairing and anion-exchange chromatography). The concentration of selenomethionine (SeMet) and total Se content were quantified (79.9 microg g(-1) (calculated as Se) and 82.9 microg g(-1), respectively). The homogeneity and stability of this candidate reference material passed the relevant tests recommended by Bureau Communautaire de Référence (BCR).