Validation of a near infrared microscopy method for the detection of animal products in feedingstuffs: results of a collaborative study

Abstract

The performance characteristics of a near infrared microscopy (NIRM) method, when applied to the detection of animal products in feedingstuffs, were determined via a collaborative study. The method delivers qualitative results in terms of the presence or absence of animal particles in feed and differentiates animal from vegetable feed ingredients on the basis of the evaluation of near infrared spectra obtained from individual particles present in the sample. The specificity ranged from 86% to 100%. The limit of detection obtained on the analysis of the sediment fraction, prepared as for the European official method, was 0.1% processed animal proteins (PAPs) in feed, since all laboratories correctly identified the positive samples. This limit has to be increased up to 2% for the analysis of samples which are not sedimented. The required sensitivity for the official control is therefore achieved in the analysis of the sediment fraction of the samples where the method can be applied for the detection of the presence of animal meal. Criteria for the classification of samples, when fewer than five spectra are found, as being of animal origin needs to be set up in order to harmonise the approach taken by the laboratories when applying NIRM for the detection of the presence of animal meal in feed.

Keywords:

• near-infrared microscopy
• inter-laboratory validation
• animal feed
• processed animal proteins

Acknowledgements

This research was carried out within the FP6 European Project SAFEED-PAP (n.d.). The information contained in this paper reflects the authors’ views; the European Commission is not liable for any use of the information contained therein. The authors would like to thank the laboratories for their participation in this collaborative study: André Kok and Oliver Maute from Bruker Optics (Brussels, Belgium); Zenling Yang and Lujia Han from the China Agricultural University (Beijing, China); Ouissam Abbas, Isabelle Fissiaux and Pascal Veys from the Walloon Agricultural Research Centre (Gembloux, Belgium); Amato Giuseppina and Daniela Marchis from the Istituto Zooprofilattico Sperimentale del Piemonte, Liguria e Valle d’Aosta (Turin, Italy); Boleslaw Slowikowski from the Joint Research Centre (Geel, Belgium); Ana Soldado and Begoña de la Roza from SERIDA (Villaviciosa, Spain); Dolores Pérez Marín and Ana Garrido Varo from the University of Córdoba (Cordoba, Spain); Jerry Sellors from Perkin Elmer (Beaconsfield, UK); and Gillian Lilley and Scott Reaney from the Veterinary Laboratories Agency (Ludddington, UK).