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Page 14 of 955 Results 131 - 140 of 9546

Y. Nia, A. Hueber, A. Abdelrahim, A.-C. Boitelle, P. Bouchez, L. Bouhier, M. Cavaiuolo, A. Fatihi, F. Guillier, S. Messio, I. Mutel, N. Vingadassalon, J.-A. Hennekinne
What place for mass spectrometry to better elucidate Food poisoning outbreaks due to bacterial toxins.

Staphylococcal food poisoning outbreaks (SFPO) are caused by the ingestion of food contaminated with staphylococcal enterotoxins (SEs) produced by strains of Staphylococcus aureus (S.aureus) . To date, 33 SEs are described in the literature but only 5 classical toxins (SEA to SEE) can be routinely detectable via commercially available immunoassays (EN ISO 19020). Liquid chromatography coupled to mass spectrometry (LC-HRMS) approach is highly specific and allows the analysis of a wide range of toxins comparing with immunoassays. In this work, we propose to develop a Multiplex method by LC-MS for the detection of SEs produced by Staphylococcus aureus strains in culture supernatant and in food matrices. In food, detection of SEs is based on selective capture by antibodies and targeted high-resolution LC-HRMS. Briefly; samples were incubated with magnetic beads coated with toxin-specific antibodies. After toxin extraction, on-bead trypsin digestion was performed and recovered peptides were analyzed by LC-HRMS. This multiplex method was optimized for 8 staphylococcal enterotoxins (SEA to SEE and SEG, SEH and SEI) for which antibodies are available in the commerce or produced in CBRN project. In the culture supernatant contaminated by toxins produced by S.aureus, LC-HRMS method based on acid precipitation protocol was developed for the detection of 24 SEs. Thus, a database of 93 specific signature peptides and LC-HRMS parameters was optimized using sequences from 24 SEs genes, including their 162 variants. Both methods LC-HRMS were tested in case of naturally contaminated samples involved in food poisoning outbreaks and detection of emerging toxins produced in culture supernatant. Results demonstrated that this method was sensitive, specific and able to detect SEs in naturally contaminated food and gave a good agreement with the official method. The LC-HRMS method showed high performance in terms of specificity, sensitivity, and accuracy when applied to 49 enterotoxin-producing strains. SE concentrations measured depended on both SE type and the coagulase-positive staphylococci (CPS) strain. This study indicates that LC-HRMS is a relevant alternative and complementary tool to ELISA methods. The advantages of LC-HRMS clearly lie in both the multiplex analysis of a large number of SEs, and the automated analysis of a high number of samples.

M. Lambert, A. Daguin, G. Quéré, A. Ducrocq, G. Morin, A. Brisard, C. Inthavong, F. Gérault, G. Lavison-Bompard
Selective analysis of dithiocarbamates by classes: overview of the French working group project

Dithiocarbamates (DTC), a class of broad-spectrum fungicides, are among the most frequently detected pesticides in the European Union, often with Maximum Residue Level (MRL) exceedances, due to their extensive use over the past decades. DTC have a polymeric structure composed of one or more metallic cations coordinated to an organic ligand whose structure allow the classification of DTC into three main groups : propylene-bis-dithiocarbamates (i.e. propineb), ethylene-bis-dithiocarbamates ( i.e.maneb, zineb, nabam, metiram, mancozeb) and dimethyl-dithiocarbamates (i.e. thiram, ziram, ferbam). DTC analyses are mostly based on the protocol of the European Reference Laboratory for Single Residue Methods (EURL-SRM, Stuttgart, Germany) which involves the acidic hydrolysis of DTC, resulting in the release of carbon disulfide (CS2) which is then quantified. However, this method has some limitations since i) naturally sulfur containing commodities (Brassicaceae, Alliaceae) or commodities subjected to sulfurization as preservative treatments may induce false-positive results or over-estimated results, and ii) this method does not allow the identification of the class of DTC involved in a positive result. In response to these limitations, some alternative methods, mostly based on the derivatization of DTC, have been published in the past few years. The French National Reference Laboratory for Single Residue Methods set up a working group at the end of 2021 with all the French official laboratories and the competent authority to assess the reliability of a methylation method (1) that should allow the quantification of DTC by classes. This method combines a decomplexation and a S-methylation step to a QuEChERS extraction, and the methylated DTC products corresponding to each of the three classes mentioned above are detected and quantified by reverse-phase LC-MS/MS analysis. The aim of this work is to investigate the critical points of the methods, from the preparation of the standards to the quantification approach, while optimizing the decomplexation/methylation steps, in order to deliver a reliable method available for controls and risk assessments studies, particularly in the actual MRL revisions context.

D. Hurtaud-Pessel, P. Couedor, A. Tollec, E. Verdon
Quantitative determination of NSAIDs residues in porcine muscle: Comparison of LCMS/MS and LC-HRMS measurement

To ensure food safety, European regulations require the monitoring of chemical contamination of foodstuffs of animal origin. This monitoring is based on a range of analytical methods capable of detecting, in particular, residues of veterinary treatment products, in order to implement national control plans. In this context, a method for monitoring Non-steroidal anti-inflammatory drugs (NSAIDs) in porcine muscle by LC-Mass spectrometry was developed for the determination of 22 target substances, including metabolites, at concentration in line with regulatory limits. Non-steroidal anti-inflammatory drugs (NSAIDs) are a class of chemically heterogeneous compounds, comprising organic acids and basic compounds. Some are authorized in food-producing animals (group B1(d) of Commission Delegated Regulation (EU) 2022/1644 and some are unauthorized (Group B3(f)). So considering their different regulatory status, range of concentration for validation was considered either between 0.1 MRL to 2 MRL, either to 0.5 MMPR to 2 MMPR, resulting in levels ranging from 0.5 µg/kg (diclofenac) for the lowest to 1000 µg/kg (carprofene) for the highest. While detection by triple quadrupole mass spectrometry is the most commonly used technology for quantitative trace measurements, high-resolution mass spectrometry, which is increasingly used in laboratories, also has real quantitative measurement capabilities. The proposed analytical method for confirmation of acidic and basic NSAIDs has been validated in accordance with the new (EU) 808/2021 Regulation, using both LC-MS/MS and LC-HRMS detection on a TSQ Vantage Triple quadrupole mass spectrometrer and a Q-Exactive mass spectrometer respectively. The appropriate acquisition mode was applied for each instrument, namely MRM mode for TSQ and FS-PRM mode for Q-exactive. The extracts prepared for the validation phase were split in two portions to enable the same extracts to be analysed on both instruments, and to enable the results to be compared. Characterization of perfomances criteria such as trueness, precision, decision limit CCa, detection capability CCβ were assessed. The quantitative performances of both technologies were very similar. Results for porcine muscle will be presented and discussed.

I. Bendhiab, A. C. Dirtu, N. Marchond, T. Guérin, P. Jitaru
A novel analytical approach for the determination of ethylene-thiourea and propylenethiourea in vegetal foodstuffs by HPLC-ICP-MS/MS

Dithiocarbamates (DTC) are one of the most largely used fungicides in agriculture as they are cost-effective against a broad spectrum of fungi and plant diseases. DTC are highly instable and they tend to decompose in foodstuffs matrix into ethylene-thiourea (ETU) and propylene-thiourea (PTU). Currently, these contaminants are determined using organic-based mass spectrometry techniques (MS or MS/MS) coupled to high performance liquid chromatography (HPLC). Due to the sulphur (S) moiety in their structure, they can also be determined using inorganic based MS techniques such as inductively coupled plasma-triple quadrupole mass spectrometry (ICP-QQQMS or ICP-MS/MS) coupled to HPLC. This study reports a novel approach allowing the simultaneous determination of ETU and PTU in fruits and vegetables by (reverse phase) HPLC coupled to ICP-MS/MS. A baseline HPLC separation of ETU and PTU was achieved in less than 5 min. A robust method validation by using the accuracy profile approach was performed by carrying out four measurement series in duplicate at six different levels over a timespan of four weeks (different days). The spike recovery factors range from 87%-101% for ETU and from 98-99% for PTU (depending on the spiking level). Good coefficients of variation in terms of repeatability and intermediate-reproducibility were also obtained. The limit of quantification was 0.022 µg kg-1 (wet weight) for ETU and 0.010 µg kg-1 (ww) for PTU. This approach was proved to be highly robust and suitable for the determination of ETU and PTU in foodstuffs of vegetal origin. In our knowledge, it is the first reported method in the literature to deal with the analysis of ETU and PTU from fruit and vegetable samples using ICP-MS based detection techniques. This novel approach opens also the possibility to apply species-specific isotope dilution, a primary method of analysis, for the determination of these organic contaminants

C. Schiavone, F. Romaniello, A. M. Rossi, C. Portesi
Metrology in support of food safety: validation of targeted and screening methods for the detection of PFAS in rice and maize

Per- and poly-fluoroalkyl substances (PFAS) are applied to food packaging and other materials to provide fat, fire, and/or water resistance properties. Emissions of PFAS from industrial wastes lead to environmental contamination. These compounds are known as "forever chemicals" due to their stability and persistence. PFAS are expected to have carcinogenic and reprotoxic effects on humans. Every day, PFAS may come into contact with people through the environment, food, and water. In summer 2022, the European Union moved forward in the fight against PFAS contamination in food and feed [1-3]. There is a need to develop increasingly sensitive and accurate analytical methods to investigate contamination levels of PFAS in the food chain to control food quality, preserve the product's safety, and prevent economic losses. The metrological approach is of paramount importance due to the lack of harmonisation and traceable methods. The aim of this study is to use a metrological approach to assess the level of PFAS contamination in rice and maize samples. The analytical method is developed on UHPLC-HRMS performing the isotopic dilution approach. All the standards were CRMs. The samples were extracted, purified and directly injected into the HPLC system. The calibration curves for the targeted method were built considering the whole budget of uncertainties. The untargeted (screening) approach was performed matching results of FullMS experiment with database and dedicated software.The method has been demonstrated to provide robust, reproducible, and reliable results.The outcomes of the targeted analysis obtained due to the linear regression resulted in a calculated average LOQ for the 21 PFAS and the 4 regulated by EFSA of 30 ng/kg and 10 ng/kg, respectively. The screening approach allowed the identification of all the new synthetical PFAS contaminants (GenX and similar) in the samples. The sensitivity, recovery and selectivity parameters obtained showed that the validated method is suitable to assess the levels of contamination of PFAS in this kind of matrix. The method was tested with proficiency testing samples from EURL-POPs. The metrological approach will be performed with real samples to assess the level of contamination in northwest Italy.

I. Bastardo Fernández, R. Chekri, J. Noireaux, P. Fisicaro, P. Jitaru
Development of a single particle ICP-MS method using a high efficiency sample introduction system (APEX TM) for the characterisation of titanium dioxide nanoparticles in foodstuffs

This work reports the development of a novel method based on single particle inductively coupled plasma-triple quadrupole mass spectrometry (ICP-QQQMS or ICP-MS/MS) using a high efficiency sample introduction system (HESIS) such as APEXTM for the characterisation of TiO2 (nano)particles (NPs) in food samples. The use of the mass shift detection mode (O2+H2 as a mixture reaction gas) avoids the isobaric interferences of 48Ca isotope hence allowing accurate characterisation of TiO2 NPs in complex matrices such the foodstuffs. APEXTM Ω proved to be an excellent approach to avoid matrix effects from food samples and provided significantly low limits of detection in size (LODsize) compared to the conventional introduction system. In order to avoid the saturation of the detector when detecting large TiO2 particles, the analyses were carried out using the forced analogue detection mode and excellent characterisation of TiO2 NPs in terms of size and concentration was achieved, with LODsize of 12 nm. The new method was applied to the analysis of a selection of foodstuffs, such as candies, sauce, cheese, cakes, etc. purchased in Spain before the ban of the use of TiO2 based additive in the European Union. In all cases, NPs recoveries were assessed based on the comparison with the total Ti level that was also measured by ICPMS in the same samples. This confirms the feasibility of this novel approach using an APEXTM Ω for the accurate characterisation of TiO2 NPs in complex matrices such as the foodstuffs and hence its application to real-life studies.

M. Menta, M. Klein, F. Auger, F. Ait-Ben-Ahmad, A. Papin, H. Biaudet, F. Séby
Size characterization and quantification of E171 titanium dioxide particles in food sauces by spICP-MS

In the food industry, titanium dioxide (E171) is used as a coloring agent, opacifier or flavor carrier in foodstuffs or as a clarifying agent in drinks. In some common foods, a fraction (5 to 50 %) of this additive has been found with a size lower than 100 nm (1). This fraction, able to cross physiological barriers and then to be accumulated in systemic organs, may cause problems with the digestive system. Thus, EFSA has concluded this additive cannot be considered safe (2). As the toxicological effects depend mainly on the size and concentration of TiO2particles, the determination of these parameters is crucial to assess the level of dietary exposure and establish appropriate risk management procedures. This study also highlighted the lack of harmonization between techniques for TiO2 nanoparticles (NPs) characterization as well as the need to develop sample preparation procedures. During the last decade, ICP-MS used in single particle mode (spICP-MS) was strongly developed and appears today as one of the most promising techniques for routine quality control of inorganic NPs in foods. Moreover, the high sensitivity and selectivity of spICP-MS allow to face the analytical challenges of food matrices.This work was focused on the optimization of sample preparation procedures allowing a quantitative extraction of TiO2 NPs from food sauces. Different extraction reagents (water, surfactants, acids, TMAH, enzymes) were studied and the potential of the spICP-MS technique was evaluated for the size characterization and quantification of NPs. The method was optimized using a white sauce and its corresponding E171 additive. The highest extracted amount of TiO2 particles was obtained using TMAH with similar TiO2 particle size distributions in the two samples showing no matrix effects during analysis. After validation, the method was applied to several sauces from the European market. Concentration values in the (0.6 6) g(TiO2)/kg range were obtained for the E171 labelled sauces with median diameters in the range 206 280 nm and a percentage of TiO2 NPs (< 100 nm) between 2 and 12 %. No titanium was detected in sauces purchased in the French market which complies with current regulations.

G. Bucher, H. El Hadri, O. Asensio, F. Auger, J.-P. Rosec
Occurrence and particle size distribution of TiO2 in various food product categories following its european ban

Following the opinion of the French Agency for Food, Environmental and Occupational Health & Safety (ANSES) on the risks associated with ingestion of food containing the food additive E171, French authorities suspended the use of this additive in food products from January 1st 2020 as a precautionary measure. Two years later Commission Regulation (EU) 2022/63 of 14 January 2022 banned the use of E171 as a food additive in the European Union. We report here the outcome of a 5-year screening (2018-2022) of 352 food samples collected on the French market by the French authorities and analysed to determine the actual presence, content and/or particle size distribution of E171 additive. Single particle inductively coupled plasma mass spectrometry (spICP-MS) analysis confirmed that E171 additive used in food products often contained significant fractions of nano-sized particles, even though 'Nano' labelling was hardly applied by the business operators. Nevertheless, determination of the total TiO2 content in food samples through the analysis of Ti by inductively coupled plasma optical emission spectroscopy (ICP-OES) demonstrated that French and European business operators were globally able to implement the 2020 French suspension and 2022 EU ban. At the same time, business operators operating outside of the EU seemed to have more difficulty in implementing the new EU rule. Thus, attention should be maintained on the TiO2 content of food products on the European market, especially for those imported from non-EU countries.

K. Cheyns, R. Nkenda, S. Van Den Neucker, J. Mast
After the ban : How to control titanium dioxide in food?

Titanium dioxide (TiO2) is applied in food as a white pigment and listed as food additive E 171. EFSA's opinion [1] states that it is not certain that its use in food is safe because it may be genotoxic. Hence, the European Commission no longer allows E 171 [2]. Consequently, authorities need analytical methods to control the absence of E 171. Because most Ti occurs in food as TiO2, screening can be realized by analyzing the total Ti content as a measure (proxy) for TiO2. This study examined whether the concentrations of total Ti are (much) larger in food products containing E 171 than in products without E 171. The rationale behind this is that the refractive properties of E 171 are only useful at relatively high amounts, requiring the addition of E 171. Challenges related to the measurement of Ti by ICP-OES in food are mainly related to sample preparation: TiO2 is practically insoluble and requires a mixture of concentrated hydrofluoric, sulfuric, and/or other acids for dissolution. However, the typically applied hydrofluoric acid solution is an ultrahazardous chemical that should be avoided for safety reasons. Hence, a digestion method using microwave digestion at 220°C in a mixture of nitric acid and sulphuric acid was optimized and evaluated for the analysis of total Ti in a variety of food samples collected before and after the ban of E 171. The measured concentrations of total Ti ranged from < 2 mg/kg to 13305 mg/kg, and from < 2 mg/kg to 26 mg/kg for foods known to contain E 171, and without added E 171, respectively. Cocoa products contained the highest natural Ti levels up to 25.5 mg/kg. When comparing four identical food items (brand, name, package) before and after the ban, the difference in total Ti concentration ranged up to 3 orders of magnitudes. Titanium concentrations above 50 mg/kg were only detected in food containing E 171. In the next phase, these analytical results will be compared with Ti concentrations measured by other analytical techniques (e.g. Raman, XRF). These results guide competent authorities in setting cut-off values when screening food products for the presence of the banned E 171 and give insights on the methods which are fit for purpose for such control.

M. Fadda, A. Sacco, A. M. Rossi, A. M. Giovannozzi
Development of novel analytical methods to trace small micron and nanoplastics in food matrices

In the last decades, our life style significantly changed, for instance in terms of consumption of convenient food or usage of single-use items. As a direct consequence, the production of plastics is globally increasing, as well as their release into the environment, threatening wildlife and human health. Most of the produced plastics are used for packaging items, from cosmetic to food applications. Up to now, the most common plastics used for packaging have been petroleum-derived, such as polyethylene (PE), polystyrene (PS), polyethylene terephthalate (PET), polyvinylchloride (PVC), polypropylene (PP) and polyamide (PA), because they have some interesting properties such as tensile and tear strength, or barrier activity against oxygen and carbon dioxide, and the cost-effectiveness [1]. However, a part from macroplastics, we are facing with the serious problem of microplastics (MPs) and nanoplastics (NPs), mainly originating by physico-chemical transformation processes, such as aging, degradation and fragmentation. Because of the ease in their detection, several studies have been conducted on larger MPs in terms of occurrence, distribution, quantification, and toxicological effects on humans identifying food as their main intake source [2]. Nowadays, research interest is going towards MPs with a diameter smaller 1 µm, called nanoplastics (NPs) that could be found in food matrices and environmental samples, by means of specific measurement techniques. Therefore, the aim of this work is to develop innovative methods to apply in the individuation, quantification and characterization of small micron and nanoplastics in food matrices, such as drinking water and milk, in the contest of PlasticTrace European project [3]. For this purpose, in this work, asymmetric flow field-flow fractionation (AF4) has been coupled with multi-angle dynamic light scattering (MADLS) and Raman spectroscopy. In particular, samples containing NPs have been separated by hydrodynamic diameter with AF4, then analyzed by MADLS to characterize their size and size distribution. Finally, the polymer type of the NPs has been identified by Raman microspectroscopy. As a side supporting technique, atomic force microscopy (AFM) has been employed to investigate the shape and the morphology of the NPs.

Page 14 of 955 Results 131 - 140 of 9546