Determination of total As, Cd, Pb, Hg, Sn and inorganic As in canned food IMEP-118 Proficiency test Report I. Fiamegkos, B. de la Calle, H. Emteborg, Corrected version J. Seghers, M.-F. Tumba, M. Vahcic, 09 / 02 / 2015 F. Cordeiro, A. Cizek-Stroh, P. Robouch January 2015 Please replace with an image illustrating your report and align it with the bottom edge of the cover. Make sure the blue JRC footer reaches the bottom of the page. Please remove this text box from your cover. Report EUR 27145 EN European Commission Joint Research Centre Institute for Reference Materials and Measurements Contact information Beatriz de la Calle Address: Joint Research Centre, Retieseweg 111 2440, Geel, Belgium E-mail: [email protected] Tel.: +32 1457 1252 https://ec.europa.eu/jrc Legal Notice This publication is a Science and Policy Report by the Joint Research Centre, the European Commission’s in-house science service. It aims to provide evidence-based scientific support to the European policy-making process. The scientific output expressed does not imply a policy position of the European Commission. Neither the European Commission nor any person acting on behalf of the Commission is responsible for the use which might be made of this publication. All images © European Union 2015 JRC94949 EUR 27145 EN ISBN 978-92-79-46355-6 (PDF) ISSN 1831-9424 (online) doi:10.2787/987731 © European Union, 2015 Reproduction is authorised provided the source is acknowledged. Printed in Belgium Abstract This report presents the outcome of the proficiency test, on the determination of total As, Cd, Pb, Hg, Sn and iAs in canned food (peas in brine). The exercise was organised by the European Union Reference Laboratory for Heavy Metals (EURL-HM) to support the Commission Regulation (EC) 1881:2006 setting maximum levels for certain contaminants in foodstuffs. Participation in the proficiency test was mandatory for the nominated NRLs, and open to other OCLs and interested laboratories. A total of 127 participants from 36 countries registered to the exercise. All NRLs (36) reported results, while 4 non-NRL participants did not. From the participating laboratories 54 % analysed the drained product and 46 % the solid/liquid composite. Hence, a non- unified analytical approach is observed. The majority of laboratories (more than 74 %) reported satisfactory results for the five scored measurands with measurable concentrations (total As, Cd, Pb, Sn and iAs). The best performances were obtained for total As, Cd and Pb. The interpretation of the respective legislation is not straightforward as indicated by the 32 laboratories that characterised the test item as compliant with the legislation, although it was not. Erratum The missing results for total Cd in the drained product (Annex 11, page 54) of laboratory N011 are included in the table of the IMEP-118 (EUR 27145) report. Dr. IOANNIS FIAMEGKOS EU-RL Heavy Metals Coordinator of IMEP-118 Determination of total As, Cd, Pb, Hg, Sn and inorganic As in canned food IMEP-118 Proficiency Test Report January 2015 Ioannis Fiamegkos (a) Beatriz de la Calle (b,c) Håkan Emteborg John Seghers Marie-France Tumba Mitja Vahcic Fernando Cordeiro (c) Aneta Cizek-Stroh (d) Piotr Robouch (c,e) (a) ILC coordinator, (b) IMEP programme coordinator, (c) Technical / scientific support, (d) Logistic support (e) EURL-HM operating manager Determination of total As, Cd, Pb, Hg, Sn and iAs in canned food Table of Contents Executive summary ............................................................................................ 4 1 Introduction .................................................................................................... 5 2 IMEP support to EU policy ............................................................................... 6 3 Scope and aim ................................................................................................. 7 4. Set up of the exercise ..................................................................................... 7 4.1 Time frame ........................................................................................... 7 4.2 Confidentiality ....................................................................................... 7 4.3 Distribution ........................................................................................... 8 4.4 Instructions to participants ...................................................................... 8 5 Test item ......................................................................................................... 8 5.1 Preparation ........................................................................................... 8 5.2 Homogeneity and stability ....................................................................... 9 6. Assigned values and their uncertainties ....................................................... 10 6.1 Assigned value X ................................................................................ 10 ref 6.2 Associated standard uncertainty u ........................................................ 11 ref 6.3 Standard deviation of the proficiency test assessment σ ............................. 14 7 Evaluation of results ...................................................................................... 14 7.1 Scores and evaluation criteria ................................................................. 14 7.2 Discussion regarding the test item (canned peas). .................................... 15 7.3 Laboratory results and scorings .............................................................. 17 7.4 Discussion on the reported results ........................................................... 22 7.5 Discussion on the information extracted from the questionnaire .................. 23 8. Compliance assessment of the test item ....................................................... 24 8 Conclusions ................................................................................................... 26 9 Acknowledgements ....................................................................................... 26 10. Abbreviations ............................................................................................. 29 11 References ................................................................................................... 30 2 Determination of total As, Cd, Pb, Hg, Sn and iAs in canned food Annexes............................................................................................................ 33 Annex 1: Invitation letter to NRLs .................................................................... 35 Annex 2: IRMM – IMEP web announcement ..................................................... 36 Annex 3: Invitation letter to EA ........................................................................ 37 Annex 4: Invitation letter to APLAC .................................................................. 39 Annex 5: Invitation letter to IAAC .................................................................... 41 Annex 6: Sample accompanying letter .............................................................. 43 Annex 7: Confirmation of receipt form.............................................................. 45 Annex 8: Questionnaire .................................................................................... 46 Annex 9: Homogeneity and stability studies ..................................................... 48 9.1 Homogeneity studies (drained product) .................................................... 48 9.2 Homogeneity studies (solid / liquid composite) ......................................... 49 9.3 Stability studies (solid/liquid composite) .................................................. 49 Annex 10: Results for total As .......................................................................... 50 Annex 11: Results for total Cd .......................................................................... 54 Annex 12: Results for total Pb .......................................................................... 58 Annex 13: Results for total Hg .......................................................................... 62 Annex 14: Results for total Sn .......................................................................... 64 Annex 15: Results for inorganic As ................................................................... 68 Annex 16: Experimental details and scoring ..................................................... 72 Annex 17: Comments of the laboratories participating in IMEP-118 ................. 98 3 Determination of total As, Cd, Pb, Hg, Sn and iAs in canned food Executive summary This report presents the outcome of a proficiency test (PT), on the determination of total As, Cd, Pb, Hg, Sn and iAs in canned food (peas in brine). The exercise was organised by the European Union Reference Laboratory for Heavy Metals for Feed and Food (EURL-HM) to support the implementation of provisions laid down in Commission Regulation (EC) No 1881/2006, which sets maximum levels for certain contaminants in foodstuffs. National Reference Laboratories (NRLs) requested the EURL-HM to organise a PT with the aim to check: (i) the analytical capabilities of participating laboratories to analyse heavy metals, in particular Sn, in vegetables and (ii) the sample preparation approach applied by NRLs and Official Control Laboratories (OCLs) when analysing canned or jarred vegetables, using the drained product or the solid/liquid composite. Participation in this PT was mandatory for the nominated NRLs, and open to official control laboratories and other interested laboratories. A total of 127 participants from 36 countries registered to the exercise. All NRLs (36) reported results, while 4 non-NRL participants did not. Laboratory results were rated using z- and ζ-scores (zeta-scores) in accordance with ISO 13528:2005. The target standard deviation for proficiency assessment (σ), for all measurands was calculated using the Horwitz equation modified by Thompson, except for the case of total Sn where σ was decided by the scientific committee of the PT. In the case of total Hg the certifying laboratories reported "less than" values, therefore no scoring was provided for this measurand. Two different sample preparation approaches have been identified: 54 % of the participating laboratories analysed the drained product, while 46 % the solid/liquid composite demonstrating the lack of specific sample preparation approach protocol. The majority of laboratories (more than 74 %) reported satisfactory results for total As, Cd, Pb, Sn and iAs. The best performances were obtained for total As, Cd and Pb. The interpretation of the respective legislation is not straightforward as indicated by the 32 laboratories that characterised the test item as compliant with the legislation, although it was not. 4 Determination of total As, Cd, Pb, Hg, Sn and iAs in canned food 1 Introduction Contamination with toxic elements is a global environmental and food safety concern. The consumption of contaminated food leads to uptake of toxic elements by humans, with the risk increasing proportional to the quantity consumed. Heavy metal toxicity can affect mental development and central nervous system function, alter the blood composition and disturb the function of organs like kidneys, lungs, and liver [1]. Heavy metals may occur in canned foods as a result of naturally incurred contamination of the food commodity or by migration from the packaging material. Metallic food packaging is mostly composed of tinplate (tin coated steel), chromium coated steel, or aluminium, which is mostly coated on the inner side with a resin to protect food from coming into contact with the metal. However, when the metal is exposed to the food as a result of damage of the coating, corrosion is accelerated and elements such as tin (Sn), iron (Fe), cadmium (Cd) and lead (Pb) could be released, increasing their levels in the food [2]. The occurrence of heavy metals in canned food is of great importance and covers a large variety of food commodities [3-7]. More specifically for tin, the general population is exposed to it through the diet with a mean tin intake ranging from <1 up to 15 mg per day. However, maximum daily intakes could reach 50–60 mg / day for individuals frequently consuming canned fruits, vegetables, and juices from un-lacquered cans. Tin levels are usually below 25 mg kg-1 in lacquered food cans, but may exceed 100 mg kg-1 in un-lacquered ones. Tin concentrations in canned foods increase with storage, time, and temperature [8]. Commission Regulation (EC) No 1881/2006 sets maximum levels for certain contaminants in foodstuffs [9]. The following limits apply: 200 mg kg-1 for tin in canned foods; 0.2 mg kg-1 for lead in legume vegetables, cereals and pulses; and 0.05 mg kg-1 for cadmium in vegetables and fruits. All values refer to wet weight. A proficiency test (IMEP-118) was organised by the European Union Reference Laboratory for Heavy Metals (EURL-HM), to assess the performance of National Reference Laboratories (NRLs) and Official Control Laboratories (OCLs) on the determination of total arsenic, cadmium, lead, mercury, tin and inorganic arsenic in canned peas. An additional outcome of this exercise consists in the evaluation of the various sample treatment approaches applied by NRLs and OCLs when analysing canned or jarred vegetables, using the drained product or the solid/liquid composite. This report summarises and evaluates the outcome of IMEP-118. 5 Determination of total As, Cd, Pb, Hg, Sn and iAs in canned food 2 IMEP support to EU policy The International Measurement Evaluation Programme (IMEP) is run by the Joint Research Centre (JRC) - Institute for Reference Materials and Measurements (IRMM). IMEP provides support to the European measurement infrastructure in the following ways: IMEP disseminates metrology from the highest level down to the field laboratories. These laboratories can benchmark their measurement result against the IMEP assigned reference value, which is established according to metrological best practice. IMEP helps laboratories to assess their estimate of measurement uncertainty. Participants are invited to report the uncertainty of their measurement results. IMEP integrates the uncertainty estimate into the scoring, and provides assistance for its interpretation. IMEP supports EU policies by organising interlaboratory comparisons (ILCs) in the frame of specific EU legislation or on request of a specific EC Directorate-General. In the case of IMEP-118 it was organised to support the Directorate General for Health and Consumers (DG SANCO) with the implementation of Commission Regulation (EC) No 1881/2006 [9]. Furthermore, IMEP-118 provided support to the following stakeholders: • The European Cooperation for Accreditation (EA) in the frame of a Collaboration of Arrangement on a number of metrological issues, including the organisation of interlaboratory comparisons. This report does not discern the EA nominees from the other participants. Their results are however summarised in a separate report to EA. • The Asia Pacific Laboratory Accreditation Cooperation (APLAC), in the frame of the collaboration with APLAC. • The Inter-American Accreditation Cooperation (IAAC). 6