NMKL at CCMAS webinar
NMKL participated in the Codex Committee on Methods of Analysis and Sampling (CCMAS) webinar series November 23-25 and our presentation is now available.
NMKL general secretariat has moved to Norway
As of 1st November 2020, the general secretariat of NMKL has moved from the Technical University of Denmark to the Institute of Marine Research in Norway. We would like to thank the former secretary general Nina Skall Nielsen and the former secretary Kirsten Becker Hansen for their great efforts during these past four years. The new secretary general is Eystein Oveland and the new secretary is Susanna Marie Petrova. We are currently working on updating all contact information on the website, and we thank you for your understanding as it takes some time to get everything in order.
Please note the new e-mail address and phone number: post@nmkl.org , +47 9026 3022
Please note that the prices listed as “kr” on the website refer to DKK. We are currently working on clarifying any ambiguities around the currencies in the webshop. Please consult the price list for prices and updated payment terms.
New NMKL-method: Total folate in food by LC-ESI-MS/MS. Quantification of 6 folate vitamers.
The standardized analytical method for folate in food has traditionally utilized quantification by a microbiological assay, a method that cannot distinguish between the different folate vitamers. This new NMKL method enables quantification of total folate based on quantification of six folate vitamers which contribute to the main folate activity. Besides providing the information about the content of the specific folate vitamers, the method includes fast extraction of folates from food that may be carried out within eight hours.
The essential part of the method is using a pure γ-glutamyl hydrolase, which enables efficient and fast break-down of the polyglutamates to monoglutamates. LC-ESI-MS/MS quantifies monoglutamates by use of 13C5-labelled internal standards.
A collaborative study was conducted in summer 2019 with participation of eight laboratories from seven European countries. The method has been successfully validated for total folate determination in strawberries, spinach, lentils, yogurt, liver and infant formula, providing acceptable Horwitz ratio values (0.60-1.94). The results are published in Food Chemistry (Ložnjak Švarc, P; Oveland, E; Strandler, HS; Kariluoto, S; Campos-Giménez, E; Ivarsen, E; Malaviole, I; Motta, C; Rychlik, M; Striegel, L; Jakobsen, J (2020): Collaborative study: Quantification of total folate in food using an efficient single-enzyme extaction combined with LC-MS/MS. Food Chemistry, 333, 127447).
Updated method: NMKL 183, Quality control test for drinking water
NMKL method 183 describes sensory quality control of drinking water. Water samples are tested against flavour-neutral reference water. If there are deviations, these are registered and a remark is given according to the nomenclature list in the method. The method is updated to now also include test settings and parameters for appearance. In addition, references have been updated.
NMKL / NordVal International and AOAC International collaboration
NMKL /NordVal International and AOAC International have signed an Agreement of Cooperation that will streamline the process for test kit companies seeking recognition from NordVal International and AOAC simultaneously.
The new agreement allows the two organizations and their respective certification programmes to jointly develop and use common evaluation protocols and select independent testing laboratories.
The goal of the cooperative agreement is to reduce the economic barrier imposed by requiring separate studies. Joint protocols mean method developers will be able to conduct testing once at one laboratory, and the data will be applicable to both AOAC and NMKL. Each organization will conduct reviews, render decisions on approvals of methods and issue certificates.
NMKL procedure No. 19, “Guidelines for sensory evaluation of food packaging”, has been updated
The guidelines in NMKL procedure No. 19 provide several different procedures, which may be applied in the sensory evaluation of food packaging, and point out critical aspects and potential pitfalls of this work. The procedure focuses mainly on the sensory aspects of packaged foods relating to odour and taste evaluation, and consequently does not deal with issues such as the design and practical usability of the packaging. The field of application is wide and covers issues such as continuous production control of incoming materials, evaluation of storage conditions for packaged goods, and controls to ensure compliance with applicable rules and regulations.
The main change in this new version of the procedure is an update of the list of references. In addition, minor editorial corrections are made on the main content.
New method: NMKL 151 Presumptive Shigella spp. Detection in foods.
NMKL 151 Presumptive Shigella spp. Detection in foods has been reintroduced and updated.
The presence of Shigella in food and the environments is normally of human fecal origin. Shigella is host-specific for higher primates, including humans. Shigella is usually present in foods in low number due to their poor ability to compete. Consequently, they are notoriously difficult to detect in foods. The infectious dose is low, and only 10-100 Shigella are needed to cause infection. Due to the low infectious dose, cross contamination from infected humans to foods and further on to more persons can occur, for example through handling of foods. Person-to-person contamination can also occur. It has been shown that Shigella can survive in weeks and months in or on different foodstuffs.
In this updated method, a step to reduce background flora and ease the isolation of Shigella for some matrices has been introduced. In addition, recommendation regarding which plates to use has been added. This method can be used for subsequent isolation of Shigella spp. after using NMKL 174, 2016, for detection of the virulence factor ipaH in enrichment broth. NMKL 174 can also be used for detection of ipaH in presumptive colonies.
3rd edition of procedure on estimation and expression of measurement uncertainty in chemical analysis available in English
When the result of a chemical analysis is presented in an analytical report it is recommended that it should always be reported as a numerical result. For the result to be complete, the measurement uncertainty of the analysis should also be included. In many cases, a result can be very hard to interpret unless accompanied by its uncertainty.
In this updated version of the procedure, guidance on how to handle bias / systematic errors in relation to measurement uncertainty is included. The principles described in Nordtest TR 537 for environmental analyzes have been introduced in the NMKL procedure and examples showing how these calculations are to be performed have been added. Whether one can or should correct for systematic errors is a complex issue, and a new section has been added to explain his. Additionally, minor restructuration and update of references have been undertaken.
A scandinavian version of this 3rd edition will follow.
New method for determination of sodium by capillary electrophoresis in foodstuffs
NMKL method No. 203 describes the determination of sodium content in foodstuffs by capillary electrophoresis (CE). The CE method is quick and needs both very little sample handling and low amount of solvents. It is applicable to various matrices such as bread, vegetables and meat products. The salt content is calculated from the sodium content with the formula: salt = 2.5 x sodium.
Sodium is extracted from sample and analysed by CE with diode array detector. The minimum content of sodium that can be detected and quantified is 0.03 g/100 g.
New method for determination of isotope dilution in foodstuffs
NMKL method No. 202, “Methylmercury: determination by isotope dilution GC-ICPMS in foodstuffs”, describes the quantitative determination of mono-methylmercury (MMHg) (10-5000 µg/kg dry weight) in mainly marine biota samples. The principle of the method is that the sample is spiked with an appropriate amount of Hg isotope-enriched MMHg and extracted. After derivatisation the sample is analysed using GC-ICPMS. The GC separates the different mercury species before MMHg is atomised and ionised in the high temperature of the ICP. The ions are extracted from the plasma, and in a mass spectrometer the ions are separated by their mass/charge ratio.