Validation of an analytical method for the determination of glyceroltriheptanoate (GTH) in processed animal by-products: Results of a collaborative study

Abstract

The performance characteristics of a method for the determination of the marker substance glycerol triheptanoate (GTH) in processed animal by-products (ABPs) based on gas chromatography (GC) coupled to mass spectrometry (MS) were determined via a collaborative study. Within the European Union, GTH needs to be added to the portion of processed ABPs that must not enter the feed and food chain (Categories 1 and 2) at a minimum concentration of 250 mg kg⁻¹ related to the fat fraction of the test samples analysed. The test materials included in the validation study consisted of three meat and bone meal (MBM) and three fat samples that contained GTH at different concentrations ranging from 61 to 455 mg kg⁻¹. The relative standard deviation of repeatability (RSD_r) varied from 3.4 to 7.8% and the relative standard deviation of reproducibility (RSD_R) varied from 9.0 to 16.5%, corresponding to HORRAT values that were, in all cases, equal or below the critical value of 2.0. The estimated trueness expressed in terms of average concentration compared to the target concentrations of GTH in all test materials varied from 95 to 107%, confirming acceptable values for the trueness of the method. Based on the acceptable values for precision and trueness, the method is fit for the intended purpose and can be used for official control purposes to determine GTH in processed animal by-products from Category 1 and Category 2.

Keywords:

• GC/MS
• inter-laboratory validation
• animal products
• glyceroltriheptanoate

Acknowledgements

We would like to thank laboratories for their participation in this collaborative study and their constructive comments on the method protocol: AGES (Wien, Austria); Federaal Laboratorium voor de Voedselveiligheid (Tervuren, Belgium); Centre Wallon de Reserches Agronomique (Gembloux, Belgium); Státní veterinární ústav (Praha, Czech Republic); Státní veterinární ústav (Jihlava, Czech Republic); Státní veterinární ústav (Olomouc, Czech Republic); Staatliches Veterinäruntersuchungsamt (Arnsberg, Germany); Landesuntersuchungsanstalt für das Gesundheits und Veterinärwesen Sachsen (Chemnitz, Germany); Bayerisches Landesamt für Gesundheit und Lebensmittelsicherheit (Oberschleißheim, Germany); Finnish Food Safety Authority (Helsinki, Finland); Laboratoire du Service Commun des Laboratoires (Rennes, France); IDAC - Institut départemental d’analyses et de conseil (Nantes, France); Laboratoire départemental d’analyses (La Roche sur Yon, France); Laboratoire départemental d’analyses et de recherché (Limoges, France); Laboratory of the Government Chemist (Teddington, UK); Agri-Food & Biosciences Institute (Belfast, UK); The Central Veterinary Research Laboratory (Celbridge, Ireland); CCL – Nutricontrol (Veghel, The Netherlands); Panstwowy Instytut Weterynaryjny w Pulawach (Pulawy, Poland); Laboratorio de medicina veterinaria (Almoster, Portugal); Veterinarska fakulteta Univerze v Ljubljani Nacionalni veterinarski institute (Ljubljana, Slovenia); State Veterinary and Food Institute (Dolny Kubin, Slovakia). We are grateful to the European Commission's DG for Health and Consumers for funding this study and more specifically to Tim Gumpel. We would like also to thank Kurt Zaman and Christophe Keppens from the Federal Agency for the Safety of the Food Chain for their support in handling the intercommunity transport permits and TRACES notification. We acknowledge the Members State's technical experts of the Commission Working Group on Animal by-Products and Chief Veterinary Officers of Member States for their support and Stephen Woodgate from the European Fat Processors and Renderers Association for his support during all phases of the project.