A rapid, semi-quantitative test for detection of raw and cooked horse meat residues Jongkit Masiri a , Lora Benoit b , Cortlandt Thienes a , Charles Kainrath a , Brianda Barrios-Lopez a , Alex Agapov a , Anatoly Dobritsa a , Cesar Nadala a , Shao-Lei Sung c , Mansour Samadpour a, b, * a Molecular Epidemiology, Inc (MEI),15300 Bothell Way NE, Lake Forest Park, WA, 98155, USA b IEH Laboratories and Consulting Group, Inc (IEH),15300 Bothell Way NE, Lake Forest Park, WA, 98155, USA c Pi Bioscientific, Inc (Pi Bio), 8315 Lake City Way NE, Seattle, WA, 98115, USA article info Article history: Received 10 November 2016 Received in revised form 17 January 2017 Accepted 19 January 2017 Available online 21 January 2017 Keywords: Adulteration Lateral flow device (LFD) Polyclonal antibodies Horse meat abstract Intentional mislabeling and adulteration of meat products with undeclared horse meat is a concern for religious, ethnic, and health reasons and is illegal under regulations mandated and enforced by food regulatory agencies and the Federal Meat Inspection Act. Nonetheless, recent analysis of the meat in- dustry has revealed an apparent increase in the frequency of meat adulteration including intentional horse meat contamination, necessitating a broader use of meat authentication testing. As existing methods for meat speciation are cumbersome and require specialized equipment and/or training, we developed a highly specific lateral flow immunoassay that can rapidly identify raw and cooked horse meat down to 0.01% and 1.0% contamination, respectively in xenogeneic meat sources in about 35 min with no false positive signals observed. Specificity analysis revealed no cross-reactivity with serum al- bumins or meat derived from chicken, turkey, pig, cow, lamb, and goat. The results of method com- parison showed that the assay had similar if not better sensitivity than the commercial ELISA kit and PCR, and required considerably less time to perform than either method. The development of a highly robust and rapid test method capable of detecting trace amounts of horse meat residues should aid food control authorities in their continued efforts to monitor for horse meat adulteration. © 2017 Elsevier Ltd. All rights reserved. 1. Introduction The issue of fraudulent incorporation of horse meat in foods intended for human consumption gained major public attention in 2013 following a meat adulteration scandal in Europe (O'Mahony, 2013; Premanandh, 2013) wherein ~5.0e7.5% of beef-based prod- ucts in Europe were documented to contain undeclared horse meat residues at contamination levels exceeding 1.0% (Walkera, Burns, & Burns, 2013). Though consumption of horse meat is not inherently harmful, unanticipated introduction of horse meat into the food supply chain increases the risk of human exposure to veterinary drug residues such as phenylbutazone (Dodman, Blondeau, & Marini, 2010) and parasites (Murrell, 2000). Additionally, con- sumption of horse meat possesses certain cultural and religious concerns, such that the practice is verboten in many countries (Simoons, 1978) and it violates the Federal Meat Inspection Act in the US. Due to increased awareness of intentional food adulteration and the need to verify labeling statements, numerous analytical techniques have been developed to perform meat authentication (Sentandreu & Sentandreu, 2014). Notably, detection platforms based on mass spectrometry, ELISA, and nucleic acid amplifica- tion have been commercialized, with detection limits ranging from 0.01e 1.0% meat contamination (von Bargen, Dojahn, Waidelich, Humpf, & Brockmeyer, 2013; K€ oppel, Ruf, & Rentsch, 2011; Premanandh, 2013). However, these methodologies are time-consuming and require specialized equipment and training to perform. Accordingly, a rapid, simple, and equally (or improved) sensitive method for detecting horse meat residues in foods is warranted, to allow assessment of meat source identi- fication throughout the process of procurement, processing, packing, distribution, and retail, so as to ensure product safety, as * Corresponding author. Molecular Epidemiology, Inc (MEI), 15300 Bothell Way NE, Lake Forest Park, WA, 98155, USA. E-mail address: msieh@iehinc.com (M. Samadpour). Contents lists available at ScienceDirect Food Control journal homepage: www.elsevier.com/locate/foodcont http://dx.doi.org/10.1016/j.foodcont.2017.01.015 0956-7135/© 2017 Elsevier Ltd. All rights reserved. Food Control 76 (2017) 102e107