IMEP-37: Determination of pesticides in grapes - Interlaboratory Comparison Report

This report presents the results of a proficiency test exercise (PT) which focussed on the determination of pesticides in grapes in support of Regulation 396/2005/EC of the European Parliament and of the Council on maximum residue levels of pesticides in or on food and feed of plant and animal origin. Eighty-seven participants from thirty-three different countries registered to the exercise, of which eighty-one reported results. From these eighty-one participants, forty were from EU countries while forty-one were from outside the EU. The test item was a grapes sample spiked with 20 selected pesticides. The assigned values were obtained as the average of results reported by five expert laboratories having demonstrated experience in the analysis of pesticides in vegetable and fruit matrices. The standard uncertainties related to the assigned values (Uref) were calculated by combining the uncertainty of the characterisation (Uchar) with a contribution for homogeneity (Ubb) and for stability (Ust). Uchar was calculated following the ISO guide 35. Laboratory results were rated with z- and zeta (ζ-) scores in accordance with ISO 13528 and ISO 17043. The z-score compares the participant's deviation from the reference value with the standard deviation for proficiency assessment (σp) used as common quality criterion, the ζ-score states if the laboratory result agrees with the assigned value within the respective uncertainty. The standard deviation for the proficiency assessment, σp, was set by the advisory board of this PT at 25% for the 20 measured pesticides based on previous experience with similar measurands. Participants were not scored for triadimenol due to the large Uref associated to the assigned value. According to the results obtained in the frame of the IMEP-37 study, the participants performed satisfactorily for the 19 scored pesticides ranging from 81 % (carbendazim) to 97 % (azoxystrobin, penconazole, pyrimethanil) of satisfactory z-scores. When analysing the results of the group of non-EU countries separately, similar results were obtained. It can be concluded that the performance in this PT is satisfactory for the laboratories world-wide.JRC.D.5-Standards for Food Bioscienc

Determination of total As, Cd, Pb and Hg in vegetable feed: IMEP-119 Proficiency Test Report

This report presents the results of a PT (IMEP-119) of the EURL-HM focussing on the determination of total As, Cd, Pb and Hg in vegetable feed in support to Directive 2002/32/EC of the European Parliament and of the Council on undesirable substances in animal feed. IMEP-119 was also opened to all laboratories who wish to take part in the exercise as a way to benchmark their performance against NRLs and other laboratories. One hundred and two participants from 45 countries registered to the exercise. Only eight participants did not report their results. Laboratory results were rated using z- and zeta (ζ-) scores in accordance with ISO 13528. The relative standard deviation for proficiency assessment was set to 15 % for the total As, Cd and Pb mass fractions, and to 22 % for the total Hg mass fraction, respectively. An overall adequate performance for NRLs and feed control laboratories is shown by the percentage of satisfactory performance (expressed as z-scores). These percentages were ranging from 93 to 74 % for NRLs and from 92 to 69 %, for feed control laboratories, respectively.JRC.D.5-Standards for Food Bioscienc

IMEP-38: Determination of total As, Cd, Pb, and Hg in compound feed - Interlaboratory Comparison Report

The Institute for Reference Materials and Measurements (IRMM) of the Joint Research Centre, a Directorate General of the European Commission, operates the International Measurement Evaluation Programme (IMEP). IMEP organizes interlaboratory comparisons (ILCs) in support to EU policies. This report presents the results of the proficiency test (PT) which focused on the determination of total As, Cd, Pb and Hg in compound feed according to Directive 2002/32/EC of the European Parliament and of the Council on undesirable substances in animal feed. The IMEP-38 exercise was organized aiming to assess the performance of food and feed control laboratories and official control laboratories. The test material used in this exercise was commercially available compound feed for cats which after the appropriate processing was spiked, bottled, labelled, numbered accordingly and dispatched to the participants on the 27th of June 2013. Forty-seven laboratories from 24 countries registered to the exercise of which 44 reported results and answered the respective questionnaire. The percentage of satisfactory z-scores ranged from 58 % (total arsenic) to 74 % (total cadmium) and the ζ-scores obtained were lower by 10 to 21%.JRC.D.5-Standards for Food Bioscienc

IMEP-114: Determination of total Cd, Pb, As, Hg and Sn in feed premixes - Interlaboratory Comparison Report

This report presents the results of the proficiency test IMEP-114 of the EU-RL-HM which focused on the determination of total Cd, Pb, As, Hg and Sn in feed premixes in support to Directive 2002/32/EC of the European Parliament and of the Council on undesirable substances in animal feed. Thirty laboratories from 26 countries registered to the exercise of which 25 reported results for total As, 30 for total Cd, 29 for total Pb, 13 for total Hg and 9 for total Sn. Laboratories were asked to perform two or three independent measurements and to report the mean, the associated uncertainty, the coverage factor of the associated uncertainty and the technique used to perform the measurements. Laboratory results were rated using z- and ζ-scores (zeta-scores) in accordance with ISO 13528. The assigned values (Xref) for the measurands were determined as the mean of the values reported by two expert laboratories. The standard deviation for proficiency assessment (σˆ ), also called target standard deviation, was set to 15 % of the assigned value, for the analytes investigated. Between 60 and 90 % of the laboratories reported satisfactory results for total As and total Cd, and 50 % for total Pb. Only 3 participants reported satisfactory results for total Sn (out of 9 laboratories that reported values). Thirteen participants reported results for total Hg although, according to the expert laboratories the mass fraction for that measurand was below their limit of detection.JRC.D-Institute for Reference Materials and Measurements (Geel

IMEP-36: Determination of total Cd, Pb, As, Hg and Sn in feed premixes: Interlaboratory Comparison Report

This report presents the results of the proficiency test IMEP-36 which focused on the determination of total Cd, Pb, As, Hg and Sn in feed premixes according to Directive 2002/32/EC of the European Parliament and of the Council on undesirable substances in animal feed. Fifty laboratories from 22 countries registered to the exercise of which 45 reported results and answered the respective questionnaire. Laboratories were asked to perform two or three independent measurements and to report the mean, the associated uncertainty, the coverage factor of the associated uncertainty and the technique used to perform the measurements. Laboratory results were rated using z- and ζ-scores (zeta-scores) in accordance with ISO 13528. The assigned values (Xref) for the measurands were determined as the mean of the values reported by two expert laboratories both of them National Metrology Institutes (NMI). The results obtained by the participants were optimum in the case of total Cd and less satisfactory for total As and total Pb. For total Sn 16 participants reported results, from which one third scored satisfactorily. Twenty one participants reported results for total Hg although, the expert laboratories reported that the mass fraction for that measurand was below their limit of detection. Hence, no scoring was provided for total Hg.JRC.D.5-Standards for Food Bioscienc

EURL-HM-22 Proficiency test report: Determination of total As, Cd, Pb, Hg, MeHg and inorganic As in fish

The European Union Reference Laboratory for Heavy Metals in Feed and Food (EURL-HM) organised a proficiency test (EURL-HM-22) for the determination of total As, Cd, Pb, Hg and inorganic As (iAs) in fish to support the Commission Regulation (EC) 1881/2006 setting maximum levels for certain contaminants in foodstuffs. This PT was open only to National Reference Laboratories (NRLs). The reference material "IAEA-436" (Tuna fish flesh homogenate) was used as test item. The finely ground dry powder material was rebottled, relabelled and dispatched to the participants. The reference values of interest were provided by the IAEA, together with an informative value for total Pb. The University of Graz (Austria) was requested to analyse the mass fraction of iAs in the material and reported a truncated value ("less than" 0.005 mg kg-1). Forty two participants from 30 countries registered to the exercise (all EU Member States plus Iceland and Norway). Only one participant could not report results due to technical instrumental problems. Laboratory results were rated using z- (z'- for MeHg) and zeta scores in accordance with ISO 13528:2015. The following relative standard deviations for proficiency assessment (σpt) were set according to the modified Horwitz equation: 13% for total Hg and MeHg; 15% for total As; and 22% for total Cd. No scoring was provided for total Pb and iAs. More than 92% of the participating NRLs reported satisfactory results (according to the z-score) for total As, Cd, Hg and MeHg, thus confirming their ability in monitoring the maximum levels set by the European Regulation (EC) No 1881/2006 for fish commodities. However, only 9 (out of 41) participants reported results for MeHg. Most of the laboratories provided realistic estimates of their measurement uncertainties.JRC.F.5-Food and Feed Complianc

Validation strategy for an ED-XRF method to determine trace elements in a wide range of organic and inorganic matrices based on fulfilment of performance criteria

This work describes the approach used to validate a method on the use of energy-dispersive X-ray fluorescence (ED-XRF) which should serve the purpose of analysing routinely trace elements in organic and inorganic matrices in a wide range of mass fractions. The following performance characteristics were determined: limit of quantification (LoQ), repeatability, intermediate precision, standard uncertainty, trueness, working range and robustness; matrix effect and selectivity were also evaluated. The method was applied to the determination of 25 elements (Al, As, Ba, Br, Ca, Cd, Cl, Cr, Cu, Fe, Hg, K, Mg, Mn, Mo, Ni, P, Pb, Rb, S, Se, Sr, Ti, Zn, Zr), in organic matrices and 12 elements (As, Br, Cd, Cr, Cu, Fe, Hg, Mn, Ni, Pb, Se, Zn,) in inorganic matrices and for mass fractions ranging from sub mg kg-1 level up to percentages, depending on the specific element. The LoQ was empirically calculated as the mass fraction for which a certain trueness and uncertainty was achieved, on the basis of information gathered from the ratios between the calculated and the certified or reference mass fractions (Ccalc/CCRM) in the calibration curves. The lowest LoQ, 0.16 mg kg-1 was achieved for Ni. Trueness was evaluated using 29 certified reference materials (CRMs) and reference materials (RMs). Repeatability and intermediate precision was found to be mass fraction-related, the higher the mass fraction the larger the repeatability/intermediate precision. The method was satisfactorily applied to the determination of trace elements in sediments, soils, cereals (wheat and rice), tobacco, feed, fish and milk.JRC.F.4-Fraud Detection and Preventio

Determination of inorganic arsenic in a wide range of food matrices using hydride generation – atomic absorption spectrometry.

The European Food Safety Authority (EFSA) underlined in its Scientific Opinion on Arsenic in Food, the need to produce arsenic speciation data for different food commodities to support dietary exposure assessment. A method, previously validated in a collaborative trial, has been applied to determine inorganic arsenic in a wide variety of food matrices, covering grains, mushrooms and food of marine origin (31 samples in total). The method is based on (i) solubilisation of the protein matrix with concentrated hydrochloric acid to allow the release of all arsenic species into solution, (ii) the subsequent extraction of the inorganic arsenic present in the acid medium using chloroform and (iii) final detection and quantification by flow injection hydride generation atomic absorption spectrometry. The method is characterized by a limit of detection of 10 µg/kg dry weight, which allowed quantification of inorganic arsenic in a large amount of food matrices. Information is provided about performance scores given to results obtained with this method and which were reported by different laboratories in several proficiency tests. The percentage of satisfactory results obtained with the discussed method is higher than that of the results obtained with other analytical approaches.JRC.F.4-Fraud Detection and Preventio

Use of energy-dispersive X-ray fluorescence combined with chemometric modelling to classify honey according to botanical variety and geographical origin

Honey is one of the food commodities most frequently affected by fraud. Although addition of extraneous sugars is the most common type of fraud, analytical methods are also needed to detect origin masking and misdescription of botanical variety. In this work, multivariate analysis of the content of certain macro-and trace elements, determined by energy dispersive X-Ray fluorescence (ED-XRF) without any type of sample treatment, were used to classify honeys according to botanical variety and geographical origin. Principal Component Analysis (PCA) and Partial Least Squares-Discriminant Analysis (PLS-DA) were used to create classification models for nine different botanical varieties: orange, robinia, lavender, rosemary, thyme, lime, chestnut, eucalyptus and manuka, and seven different geographical origins: Italy, Romania, Spain, Portugal, France, Hungary and New Zealand. Although characterised by 100 % sensitivity, PCA models lacked specificity. The PLS-DA models constructed for specific combinations of botanical variety-country (BV-C) allowed the successful classification of honey samples, which was verified by external validation samples.JRC.F.4-Fraud Detection and Preventio

Authentication of PDO paprika powder (Pimenton ´ de la Vera) by multivariate analysis of the elemental fingerprint determined by ED-XRF. A feasibility study

Products with a Protected Denomination of Origin (PDO) are vulnerable to misdescription of their true geographical origin. In this work a method has been developed that allows the authentication of La Vera paprika powder (Pimentón de la Vera), a PDO product from the central-west Spanish region, Extremadura. The mass fractions of Br, Ca, Cs, Cl, Cu, Fe, K, Mg, Mn, Ni, P, Rb, S, Sb, Sr and Zn determined by energy dispersive X-ray fluorescence (ED-XRF) are used for classification purposes by multivariate analysis using Principal Component (PCA) and Partial Least Square-Discriminant Analysis (PLS-DA). Forty-five paprika samples purchased in supermarkets around Europe were used to build up the models for prediction purposes. The PCA model for verifying the origin of paprika labelled as La Vera had a sensitivity of 73 %, a specificity of 100 % and an accuracy of 86.5 %, whereas the PLS-DA model had a sensitivity, a specificity and an accuracy of 100 %, which demonstrates the utility of the approach for verifying. The models constructed with PLS-DA allow the satisfactory authentication of all La Vera paprika included in this study.JRC.F.4-Fraud Detection and Preventio