Analytical Methods Metabolomic approach for the detection of mechanically recovered meat in food products Izabella Surowiec, Paul D. Fraser, Raj Patel, John Halket, Peter M. Bramley ⇑ School of Biological Sciences, Royal Holloway University of London, Egham, Surrey TW20 0EX, UK article info Article history: Received 14 March 2010 Received in revised form 6 October 2010 Accepted 13 October 2010 Keywords: Metabolomics Meat analysis Mechanically recovered meat Hand-deboned meat Desinewed meat GC–MS OPLS-DA PCA abstract Mechanically recovered meat (MRM) is generated by mechanical treatment of remnants following hand deboning. EU regulations exclude MRM from the definition of meat; as a consequence there is a need for robust analytical procedures to differentiate MRM from hand-deboned meat (HDM) and desinewed meat. Present study represents the development of an analytical platform for the detection of adulteration of meat products with MRM. Small molecular weight compounds were extracted from meat samples and analysed using GC–MS. Obtained metabolite profiles were modelled with OPLS-DA for the accurate clas- sification of MRM, HDM and desinewed pork and chicken samples. Separation of three classes of products for fresh chicken and pork meat samples was achieved. In addition, the procedure also enabled proper prediction of samples not included in the model as well as pork commercial meat products. Compounds that could be potential markers for MRM detection in commercial products were also selected. Ó 2010 Elsevier Ltd. All rights reserved. 1. Introduction Mechanically recovered meat (MRM) is defined as ‘‘residual material, off bones, obtained by machines operating on auger, hydraulic or other pressure principles in such a manner that the structure of the material is broken down sufficiently for it to flow in puree form from the bone” (British Meat Manufacturers Association, 1991). This paste-like meat product is produced by forc- ing beef, pork or chicken bones, with attached edible meat, under high pressure through a sieve or similar device to separate the bone from the edible meat tissue. Such material offers the food industry a means of reducing cost through the incorporation of cheaper ingre- dients and has thus been used in comminuted meat-based products such as meat pies, sausages and so-called ‘economy burgers’. The most commonly used materials for MRM production to date are chicken and pork carcasses. Bovine material has been banned as it is potentially a source of bovine spongiform encephalopathy. For MRM production usually only the vertebrae, ribs, shoulder blade and the pelvis are used. The machines used to recover the residual meat vary in design and action. Many use a piston to sub- ject bones to very high pressure in order to extract the flesh. The resultant slurry is then passed through a series of sieves designed to filter out any large particles. Any connective tissue or collagen is also removed at this point, being a by-product of the process. The end product of the process looks more like slurry than a recognised traditional ‘piece of meat’. Recently, milder production technologies for meat recovery have been used, and the product obtained usually has low calcium (bone) content and its structure is similar to that of minced meat. This product is produced under lower pressures than MRM and is defined as desinewed meat. Desinewed meat under EU regulations falls under the definition of meat and hence does not need to be la- belled separately (Regulation (EC) No 853/2004). Consumer con- cerns about the safety of MRM consumption as well as its aesthetic perception, have led however to the exclusion of MRM from the EU definition of meat. In doing so, clear and separate labelling of MRM in products is required. In order to enforce this legislation, robust analytical procedures are needed to differentiate MRM from both hand-deboned meat (HDM) and desinewed meat. This is not an easy task considering natural variation within and between animal species, different pre-treatment conditions of the carcasses, various machine types and operating settings used in MRM production, together with the fact that MRM should be now differentiated not only from hand-deboned meat but also from the more similar material, desinewed meat. Numerous approaches have been employed to differentiate MRM from HDM. A histological approach has been developed that exploits changes in meat properties arising during the mechanical production process. For example, disappearance of muscle fibres or changes in their structure can take place; concurrently the appear- ance of bone fragments and bone-associated tissues can occur. 0308-8146/$ - see front matter Ó 2010 Elsevier Ltd. All rights reserved. doi:10.1016/j.foodchem.2010.10.064 ⇑ Corresponding author. Fax: +44 1784 414224. E-mail address: P.Bramley@rhul.ac.uk (P.M. Bramley). Food Chemistry 125 (2011) 1468–1475 Contents lists available at ScienceDirect Food Chemistry journal homepage: www.elsevier.com/locate/foodchem