Petra Gowik

Trends in the identification of organic residues and contaminants: EC regulations under revision

The use of identification points (IPs) is a new approach to set up quality criteria for the identification of organic residues and contaminants: a laboratory is allowed to use any molecular spectrometric technique or combination of techniques in order to earn a minimum number of points. The system of IPs balances the identification power of the different analytical techniques and has the advantage that new techniques can be introduced very easily.

Validation of a multi-residue method for the determination of several antibiotic groups in honey by LC-MS/MS

The presented multi-method was developed for the confirmation of 37 antibiotic substances from the six antibiotic groups: macrolides, lincosamides, quinolones, tetracyclines, pleuromutilines and diamino-pyrimidine derivatives. All substances were analysed simultaneously in a single analytical run with the same procedure, including an extraction with buffer, a clean-up by solid-phase extraction, and the measurement by liquid chromatography tandem mass spectrometry in ESI+ mode. The method was validated on the basis of an in-house validation concept with factorial design by combination of seven factors to check the robustness in a concentration range of 5–50xa0μgxa0kg−1. The honeys used were of different types with regard to colour and origin. The values calculated for the validation parameters—decision limit CCα (range, 7.5–12.9xa0μgxa0kg−1), detection capability CCβ (range, 9.4–19.9xa0μgxa0kg−1), within-laboratory reproducibility RSDwR (<20% except for tulathromycin with 23.5% and tylvalosin with 21.4 %), repeatability RSDr (<20% except for tylvalosin with 21.1%), and recovery (range, 92–106%)—were acceptable and in agreement with the criteria of Commission Decision 2002/657/EC. The validation results showed that the method was applicable for the residue analysis of antibiotics in honey to substances with and without recommended concentrations, although some changes had been tested during validation to determine the robustness of the method.

A new profile likelihood confidence interval for the mean probability of detection in collaborative studies of binary test methods

A confidence interval for the probability of detection across laboratories (LPOD) for qualitative methods, described in the AOAC INTERNATIONAL guidelines for validation of microbiological methods for food and environmental surfaces, is considered. It is demonstrated that under certain conditions, the observed confidence of this confidence interval can be rather low, so that statistical minimum requirements are not fulfilled. A new profile likelihood confidence interval based on a latent random laboratory effect approach is proposed. Observed confidence levels for this confidence interval demonstrate its applicability already for a small number of laboratories.

Determination of chloramphenicol residues in crustaceans: preparation and evaluation of a proficiency test in Germany.

Chloramphenicol (CAP) is banned for use in food-producing animals and is, thus, controlled on the basis of the National Residue Control Plans in the European Union. Due to current problems with residues of CAP in shrimp, crayfish and prawns, a sensitive GC/NCI/MS method was optimised and in-house validated. The validation study resulted in a decision limit (CCα) of 0.07u2009µgu2009kg−1, a recovery of 95% and a within-laboratory reproducibility of 9%. The method was used for preparing a proficiency test to assess the quality of residue control in Germany. The proficiency test involved analysis of five samples and the results were very satisfactory. The reproducibility standard deviation for five samples ranged from 17 to 24%, and the median concentrations lay between 0.43 and 0.51u2009µgu2009kg−1 CAP. These values are clearly below the corresponding Horwitz standard deviation of about 50%. From the study, it can be concluded that there are, irrespective of the method applied, well-established and proper working analytical procedures for the control of CAP around the minimum required performance limit (MRPL) of 0.3u2009µgu2009kg−1.

Tasks of the NRLs with respect to crisis management: contribution of the EURL/NRL at the BVL as exemplified by the horse meat scandal

According to Art. 32 and 33 of Regulation (EC) No. 882/2004, the European Union and National Reference Laboratory for Pharmacologically Active Substances (EURL/NRL) at the Federal Office of Consumer Protection and Food Safety (BVL) is responsible, among other tasks, for supporting the official control laboratories as well as the competent authorities on a national and EU level. It is thus an important instrument in the overall complex of crisis management. Immediately after the publication of the first rapid alerts in the framework of the European Rapid Alert System for Food and Feed (RASFF), the EURL provided advice to the responsible Commission service with respect to the wording of the Commission Recommendation of 19 February 2013 on a coordinated control plan with a view to establish the prevalence of fraudulent practices in the marketing of certain foods, by detailing the available analytical means and capacities. In connection with the consumer fraud regarding the undeclared presence of horse meat in beef products (convenience food), a possible risk emanating from the non-authorised use of phenylbutazone (PBZ) was taken into consideration. For this reason the Commission Recommendation of 19 February 2013 suggested that at least one sample for every 50 tonnes of horse meat should be tested, each Member State (MS) being required to carry out a minimum of five tests. Moreover there was need for an analysis for PBZ in processed products containing horse meat as undeclared ingredient. The EURL/NRL of the BVL supported the analytical activities of the German control laboratories as well as of the European National Reference Laboratories (NRLs) through numerous measures.ZusammenfassungDas Europäische und nationale Referenzlabor für Rückstände pharmakologisch wirksamer Stoffe (EURL/NRL) im Bundesamt für Verbraucherschutz und Lebensmittelsicherheit (BVL) ist gemäß Art. 32 und 33 der Verordnung (EG) Nr. 882/2004 unter anderem zur Unterstützung der amtlichen Untersuchungseinrichtungen sowie der zuständigen Stellen auf Bundes- und auf EU-Ebene verpflichtet und somit ein wertvolles Instrument im Bereich des Gesamtkomplexes „Krisenmanagement“. Unmittelbar nach Erscheinen der ersten Schnellwarnungen im Europäischen Schnellwarnsystem für Lebens- und Futtermittel (RASFF) hat das EURL die zuständige Kommissionsdienststelle bei der Ausformulierung der Empfehlung der Kommission vom 19. Februar 2013 über einen koordinierten Kontrollplan zur Feststellung der Verbreitung betrügerischer Praktiken bei der Vermarktung bestimmter Lebensmittel hinsichtlich der verfügbaren analytischen Möglichkeiten und Kapazitäten beraten. Im Zusammenhang mit der Verbrauchertäuschung zum nicht deklarierten Einsatz von Pferdefleisch in Rindfleischerzeugnissen (Fertiggerichten) wurde ein mögliches Risiko durch einen nicht zugelassenen Einsatz von Phenylbutazon (PBZ) in Betracht gezogen. Aus diesem Grund wurde den Mitgliedstaaten in der Empfehlung der Kommission vom 19. Februar 2013 vorgeschlagen, dass die Mindestzahl der zu ziehenden Proben eine Probe je 50 t Erzeugnis sein soll, wobei je Mitgliedsstaat mindestens fünf Proben gezogen werden sollen. Darüber hinaus bestand Bedarf an der Untersuchung auf PBZ in verarbeiteten Produkten, die Pferdefleisch als nicht deklarierte Zutat enthielten. Die Untersuchungsaktivitäten sowohl der deutschen Untersuchungseinrichtungen der Länder als auch der europäischen nationalen Referenzlaboratorien (NRL) wurden durch zahlreiche Maßnahmen vom EURL/NRL des BVL unterstützt.

Final report on key comparison CCQM-K81: Chloramphenicol in pig muscle

Under the auspices of the Organic Analysis Working Group (OAWG) of the Comit? Consultatif pour la Quantit? de Mati?re (CCQM) a key comparison, CCQM-K81 Chloramphenicol in pig muscle, was coordinated by BVL and PTB in 2009/2010. Six NMIs/DIs participated in this comparison. Chloramphenicol (CAP) is an effective broad-spectrum antibiotic which can in principle be used for the treatment of humans and animals. Its use for the treatment of food-producing animals is, however, forbidden worldwide in many countries due to potential severe side effects. The key comparison was the follow-up to the successful pilot study CCQM-P90: chloramphenicol in milk. With this key comparison it was intended to demonstrate the capability of NMIs/DIs to analyse traces of CAP in food at concentration levels resulting from legal requirements for food control. Additionally, the quality of this kind of analysis with respect to compliance with legal requirements for food control methods and the international comparability of measurements should be evaluated in general. The study was classified as a track C study (studies in emerging areas of global interest). For the study incurred lyophilised pig muscle material containing CAP (at a mass-fraction level around the maximum allowable level for import for a number of countries) has been produced as a candidate reference material by BVL and IRMM (Institute for Reference Materials and Measurements, JRC of the European Commission). Animal treatment and slaughtering of the animal to gain incurred muscle material as well as pre-testing of the CAP content was done at the BVL. The IRMM did further processing of the material and testing of homogeneity and stability. Participants were invited to assign the mass fraction of free CAP in the comparison sample. CCQM-K81 demonstrated successfully the capability of the participating laboratories to assign chloramphenicol values in tissue down to residue levels of around 0.3 ng/g (referring to the analyte content in reconstituted muscle material). Although very different sample preparation techniques (different pre-treatments, defattening steps, cartridges, solvents) as well as different analytical techniques (LC-MSMS, GC-MS, different instruments, columns, eluents) were applied to detect chloramphenicol at a very low concentration level, a KCRV of 0.267 ng/g with a satisfying expanded uncertainty of 17.4% was ascertained. Two of the reported results were not eligible to be used in establishing the KCRV; anyhow the KCRV as estimated from just the eligible results agrees very well with the additional results. With respect to legal requirements for quantitative methods for residue control in food the key comparison results prove the capabilities of the laboratories to fulfil these settings with highest precision and to provide calibration and measurement services to residue control laboratories. Main text. To reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database kcdb.bipm.org/. The final report has been peer-reviewed and approved for publication by the CCQM, according to the provisions of the CIPM Mutual Recognition Arrangement (CIPM MRA).

Factorial interlaboratory tests for microbiological measurement methods@@@Faktorielle Ringversuche zur Validierung mikrobiologischer Methoden

This paper presents a validation approach for microbiological methods based on a combination of interlaboratory tests and factorial experiments. It requires not more than 4 participants but is achieving comparable statistical confidence as in method validation studies with 8–12 participants, if properly designed. The approach is illustrated by a comprehensive validation of the Arxula adeninivorans yeast estrogen screen (A-YES) assay for the detection of estrogenic activity in mineral water.ZusammenfassungIn dieser Arbeit wird ein Validierungsansatz für mikrobiologische Methoden vorgeschlagen, bei dem ein Ringversuch mit einem faktoriellen Experiment kombiniert wird. Dieser Ansatz ermöglicht eine deutliche Reduzierung der Anzahl der teilnehmenden Laboratorien: Bei geeignetem Versuchsdesign werden nur 4 anstelle von 8–12 Teilnehmern wie in gewöhnlichen Ringversuchen benötigt. Der Ansatz wird anhand einer Validierung des Arxula adeninivorans Hefe Assay (A-YES) zum Nachweis östrogener Aktivität in Mineralwasser illustriert.