Investigation of methods to detect mechanically recovered meat in meat products - I: Chemical composition

The proximate composition (fat, moisture, nitrogen, ash and collagen) and the calcium, iron and total purine contents of samples of mechanically recovered meat (MRM) derived from beef, lamb, pork, chicken and turkey were analysed. The data obtained illustrate the variability in the composition of mechanically recovered meats derived from different meat species. The effect of including a high proportion of bones containing marrow in the starting material, the effect of recovery machine type (Yieldmaster and Protecon) and the effect of employing different operating conditions, were investigated. MRM produced using the Yieldmaster machine was generally found to contain higher concentrations of ash and calcium than that produced using the Protecon machine. Although operating conditions appeared to have little effect on the composition of mechanically recovered chicken meat, some differences were identified in mechanically recovered turkey and pork produced under different conditions. Comparison of the composition of MRM with that of meat removed manually, from close to the bone, from similar source materials highlighted a number of differences between the     

Metabolomic approach for the detection of mechanically recovered meat in food products

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 classification 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.     

Proteomic approach for the detection of chicken mechanically recovered meat

Mechanically recovered meat is cheaper than raw meat and thus has been incorporated into many meat-derived products. EU regulations exclude mechanically recovered meat from the definition of meat; as a consequence analytical procedures are needed to differentiate it from hand-deboned meat. The present pilot study has utilized a proteomic approach to find potential markers for the detection of chicken mechanically recovered meat. Intact proteins were extracted from raw meat and then analyzed with OFF-GEL electrophoresis followed by SDS-PAGE and identification of potential markers by nano-LC-MS/MS. It was shown that it is possible to extract, separate and identify key proteins from processed meat material. Potential chicken mechanically recovered meat markers--hemoglobin subunits and those similar to myosin-binding protein C were also identified.     

Bone marrow measurements for mechanically recovered products from machines that press bones

Meat from Advanced Meat Recovery (AMR) systems is being used in increasing amounts in meat products, but authenticity issues resulting from the incidental inclusion of bone marrow when meat is pressed from the bones have arisen. Unfortunately, no widely accepted method for determining amount of marrow in meat from AMR systems is available. Past attempts to detect and quantify the amount of marrow in mechanically recovered products is the focus of this review. Methods for quantifying red marrow include those based on the heme pigments and on iron contained in these pigments. An immunological procedure in which antibodies are raised to bone marrow proteins and the pH method can also be used as qualitative and quantitative tests, respectively, for red marrow presence. Fatty marrow, associated with the term marrow by the public, is found in the medullary cavity of the shaft of long bones. These bones are not recommended for use in meat recovery systems, so methods for detection of fatty marrow are not addressed.     

Investigation of methods to detect mechanically recovered meat in meat products — III: Microscopy

This was a preliminary study to investigate whether hyaline cartilage could be easily identified in mechanically recovered meat (MRM) and whether its presence could be used as a possible marker for MRM in meat products. MRMs produced from beef, pork, lamb, chicken and turkey, using a variety of machine types and processing conditions, were compared to both minced and colloid milled hand-deboned samples, using a chemical staining technique followed by examination using the light microscope. The methodology was tested on various mixtures of MRM and hand-deboned meat. Although this technique, as with most microscopy techniques generally, is not suitable for quantitative determinations, the results indicate that light microscopy could be used as a useful screening method.     

Investigation of methods to detect mechanically recovered meat in meat products - II: Gel electrophoresis

This study investigated the use of sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDS-PAGE) as a method for differentiating between mechanically recovered and hand deboned meat. Twenty-nine samples of mechanically recovered meat (MRM), including some heat treated samples, were obtained. The samples were derived from several animal species and processed using different machine types and a range of processing conditions. They were examined using SDS-PAGE and the separation patterns obtained compared with those of hand deboned meat (HDM) reference samples. There were obvious differences in the relative intensities of several bands within the profiles obtained which distinguished MRM from HDM. These were more obvious for red meat than poultry meat samples. A few differences were found between MRM samples produced using different machines but no apparent differences between samples produced using different machine operating conditions were observed. The technique was tested using composite MRM-HDM mixtures. It was possible to suggest an order of percentage incorporation of MRM at levels of down to 5–10% for red meat and 25% for poultry meat. With further development and refinement, it may be possible to use the technique to detect and possibly quantify MRM present in all types of meat products, including cooked meat products.     

Very fast chilling of beef: effects on meat quality

This study investigated the use of capillary gel electrophoresis (CGE) as a method for differentiating between raw mechanically recovered chicken meat (MRM) and hand deboned chicken breast meat (HDM). Twenty samples of MRM were obtained and twenty samples of HDM were prepared in the laboratory. They were extracted and analysed using Prosort? SDS-protein analysis reagent. There were obvious differences in the relative peak areas within the profiles obtained which distinguished raw MRM from raw HDM; specifically, that of haemoglobin was higher in MRM. Using the peak area of haemoglobin and its ratio to other peaks, the technique was tested using composite MRM-HDM mixtures. The results suggest that it is possible to differentiate mixtures containing 7.5% MRM from that of 0% MRM using the CGE method.     

Assessing the quality of mechanically and manually recovered chicken meat

The biochemical composition and histological characteristics of meat recovered mechanically by the auger/sieve (a/s) and the hollow drum/belt (hd/b) principles from two different chicken carcass parts were compared with meat recovered manually. The quality of meat recovered mechanically by the hollow drum/belt principle was equal to or higher than the quality of manually recovered meat. The degradation of muscle structure was highest in the meat recovered by the a/s principle and lowest in the manually recovered meat. For the biochemical measurements with the exception of collagen, determinations of a single sample were sufficient to achieve a repeatability of 0.9, whereas for the histological measurements at least 8 samples were necessary. It is suggested that a quality-grading scale based on biochemical composition and level of degradation of muscle fibre structure should be established for all types of minced meat regardless of whether the meat is obtained by mechanical or manual procedures and that legislation concerning the use of MRM should be based on such a scale.     

Immunological detection of keratan sulfate in meat products with and without mechanically separated chicken meat

Keratan sulfate is a glycosaminoglycan found in the structure of cartilage proteoglycans, aggrecan and fibromodulin. This study was undertaken to detect this glycosaminoglycan in meat products containing mechanically separated chicken meat (MSCM) having cartilage particles. Dry-defatted samples of MSCM and meat products with or without MSCM were digested with papain, and a non-dialyzable fraction from each papain digest was examined by immunodiffusion analysis using anti-keratan sulfate monoclonal antibody (IgM). No precipitine line was formed with the antibody for all samples of meat products without MSCM, while a sample of MSCM and all samples of meat products with MSCM gave clear precipitine lines with the antibody. The immunodiffusion test described here appears to be a simple sensitive specific method for qualitative analysis of keratan sulfate, which in combination with other methods may be useful for detection of MSCM in meat products.     

Immunological detection of keratan sulfate in meat products with and without mechanically separated chicken meat

Keratan sulfate is a glycosaminoglycan found in the structure of cartilage proteoglycans, aggrecan and fibromodulin. This study was undertaken to detect this glycosaminoglycan in meat products containing mechanically separated chicken meat (MSCM) having cartilage particles. Dry-defatted samples of MSCM and meat products with or without MSCM were digested with papain, and a non-dialyzable fraction from each papain digest was examined by immunodiffusion analysis using anti-keratan sulfate monoclonal antibody (IgM). No precipitine line was formed with the antibody for all samples of meat products without MSCM, while a sample of MSCM and all samples of meat products with MSCM gave clear precipitine lines with the antibody. The immunodiffusion test described here appears to be a simple sensitive specific method for qualitative analysis of keratan sulfate, which in combination with other methods may be useful for detection of MSCM in meat products.     

Optimization of conditions for myofibril preparation from mechanically recovered chicken meat

The influence of various conditions affecting the isolation of a myofibrillar preparation (MP) from chicken mechanically recovered meat (MRM), i.e. the time of additional chopping in a bowel chopper, washing time, the number of washings, and the water to MRM ratio, on the recovery of dry matter and myofibrillar protein, and fat content in the preparation was investigated. The following particular steps were determined to be the most desirable parameters: chopping MRM for 10 minutes, washing time of 15 minutes, 3 (or 2) consecutive washings, 3:1 water to MRM ratio (v/w). Under these conditions a significant decrease of fat content (93% on average) was found in comparison to the content in MRM. The removal of fat, sarcoplasmic protein and connective tissue increased the concentration of myofibrillar protein. The number of aqueous washings of MRM had the biggest influence on the protein and fat content in the concentrate. Electrophoretic analysis (SDS-PAGE) of protein in the preparation obtained under optimal conditions showed that myosin heavy chains (MHC) and actin constituted approximately 50% of all the proteins in the preparation.     

Determination of soybean proteins in commercial heat-processed meat products prepared with chicken,beef or complex mixtures of meats from different species

The addition of foreign proteins (mainly soybean proteins and milk proteins) to heat-processed meat products is a common practice. This work approaches the determination of additions of soybean proteins in heat-processed meat products prepared with chicken meat, beef meat, and complex mixtures of meats from different species (chicken, pork, beef, and turkey) by perfusion reversed-phase high-performance liquid chromatography. The applied method was previously developed for the determination of soybean proteins in pork and turkey meat products but it has never been tested for the determination of soybean proteins in other heat-processed meat products containing other kinds of meats. This paper demonstrates the validity of this method for the detection of soybean proteins in heat-processed meat products containing different varieties of meats and even in the presence of other foreign proteins such as milk proteins. The specificity and existence of matrix interferences have been checked for these samples and accuracy has been evaluated by the comparison of the soybean protein contents determined by the proposed method and the official ELISA method.     

Influence of the addition of mechanically recovered meat on the physico-chemical properties of meat model blends

The physico-chemical properties of meat model blends (basic composition: fresh lean pork, pork back fat, 2% NaCl, water with ice), with added mechanically recovered pork (MRM), were studied. Fresh MRM was added at levels of 10% and 20% substitution of meat protein with or without further substitution by 10% sodium caseinate or soya isolate. The addition of MRM to meat blends caused an increase in the pH, the water-holding capacity, the viscosity, the dominant wavelength and colour purity. No effects on emulsifying capacity were observed but thermal cooking losses and lightness of colour were reduced. The addition of blends of MRM and soya isolate or sodium caseinate caused lower values of the investigated features than those observed when only MRM was used.     

Detection of chicken meat in raw meat mixtures by a sandwich enzyme immunoassay

A double-antibody sandwich ELISA (enzyme-linked immunosorbent assay) has been successfully developed for the detection of low levels of chicken meat (1–30%) in unheated meat mixtures. The assay uses chicken-specific antibodies, obtained by immunoadsorption of the crude chicken antisera onto immobilized sarcoplasmic extracts from beef, pig and horse, to remove cross-reacting antibodies. The purified antibodies, bound to the wells of a microtitre plate, sequester chicken muscle soluble proteins from saline extracts of meat mixtures. Immuno-recognition is made with similar purified antibodies conjugated to the enzyme horseradish peroxidase. Subsequent enzymic conversion of substrate gives clear optical density differences, when assaying minced beef and pig containing variable amounts of chicken meat.     

Production of a horse-specific monoclonal antibody and detection of horse meat in raw meat mixtures by an indirect ELISA

A stable hybridoma cell line (DD3) has been produced secreting a monoclonal antibody specific for horse muscle proteins. The DD3 monoclonal antibody (mAb) did not show significant cross-reactivity when tested against beef, chicken, pig and soya proteins or bovine caseins, gelatine and bovine serum albumin. The DD3 mAb was used in an indirect ELISA format for the detection of defined amounts of horse meat (10–500 g kg-¹) in beef meat mixtures. Immunorecognition of monoclonal antibodies adsorbed to horse meat adsorbed onto the ELISA plate was made with rabbit anti-mouse immunoglobulins conjugated to the enzyme horseradish peroxidase. Subsequent enzymic conversion of the substrate gave clear optical density differences when assaying mixtures of minced beef containing different amounts of horse meat.     

Lead and cadmium in meat and meat products consumed by the population in Tenerife Island, Spain

The aim of this study was to determine the levels of lead and cadmium in chicken, pork, beef, lamb and turkey samples (both meat and meat products), collected in the island of Tenerife (Spain). Lead and cadmium were measured by graphite furnace atomic absorption spectrometry (GFAAS). Mean concentrations of lead and cadmium were 6.94 and 1.68 µg kg^-1 in chicken meat, 5.00 and 5.49 µg kg^-1 in pork meat, 1.91 and 1.90 µg kg^-1 in beef meat and 1.35 and 1.22 µg kg^-1 in lamb meat samples, respectively. Lead was below the detection limit in turkey samples and mean cadmium concentration was 5.49 µg kg^-1. Mean concentrations of lead and cadmium in chicken meat product samples were 3.16 and 4.15 µg kg^-1, 4.89 and 6.50 µg kg^-1 in pork meat product, 6.72 and 4.76 µg kg^-1 in beef meat product and 9.12 and 5.98 µg kg^-1 in turkey meat product samples, respectively. The percentage contribution of the two considered metals to provisional tolerable weekly intake (PTWI) was calculated for meat and meat products. Statistically significant differences were found for lead content in meats between the chicken and pork groups and the turkey and beef groups, whereas for cadmium concentrations in meats, significant differences were observed between the turkey and chicken, beef and lamb groups. In meat products, no clear differences were observed for lead and cadmium between the various groups.     

The separation of meat from bone-A review of the mechanics and the problems

With continually increasing demands on the world's food supply, new techniques, improvements to old methods, the recovery and utilisation of waste and the introduction of novel foods are all becoming increasingly important. The separation of residual meat from bone by manual methods is inefficient, time-consuming and expensive; mechanical separation is not new, but it is only in recent years that manufacturers have become aware of its potential. There are two main approaches to meat recovery, removal of bone from meat and retrieval of meat from bones. Although the implications of the former are significant, the available methods are largely modifications of manual procedures and limited in application; recovery of meat from bones is, however, in extensive commercial use. This review discusses the methods and mechanics of the latter and the associated problems of handling, storage and recovery, together with the uses of the product, legal requirements and restrictions in the use of mechanically recovered meat (MRM).     

Ash and calcium as measures of bone in meat and bone mixtures

Bone content of mechanically recovered meat is usually controlled by setting calcium limits, but these limits may allow more bone in some products because calcium content of fresh bone is variable. Studies involving deposition of energy, nutrients, and minerals are also dependent on ash or calcium to determine bone content of carcasses. However, ash and calcium, which is 37% of bone ash, varies by age of animal, presence or absence of tissues such as marrow or cartilage that are associated with bone, and state of bone hydration. Literature that reports ash content of bone and factors associated with its variability is the focus of this review. Based on the literature reviewed, a conversion factor of 4.5 for calcium percentage to fresh cortical bone percentage from round bones of cows, fed beef, lambs, pigs and hens is recommended. A conversion factor of calcium percentage to fresh bone percentage of 5.0 is recommended for all veal and broiler bones and for flat bones.     

An Enzyme Immunoassay Technique for Detection of Salmonellae in Meat and Poultry Products

A commercially available enzyme immunoassay (ELISA) in which a myeloma protein (MOPC 467) is used for detection of salmonellae was compared with two conventional cultural methods for detection of salmonellae in naturally contaminated meat and poultry products. Products tested included mechanically deboned poultry, chitterlings, poultry carcass rinsings, chicken necks, luncheon loaf emulsion, pork sausage and basturma. There was 100% agreement between ELISA and cultural methods. The ELISA technique is specific and rapid. Identification of Salmonella-contaminated meat and poultry products was accomplished in 2-3 days compared to the 4-6 days required by conventional cultural methods.     

Detection of mechanically recovered meat and head meat from cattle in ground beef mixtures by multivariate analysis of isoelectric focusing protein profiles

The present work investigates the possibility of constructing a multivariate calibration model for predicting the composition of ground beef with respect to different meat quality types, based on intensity profiles from isoelectric focusing of water-soluble proteins. Beef mixtures containing various amounts of mechanically recovered meat, head meat and production meat from beef, were analysed by isoelectric focusing in immobilised pH-gradients. The gels were photographed and the images transferred to a digital format. By simple image processing procedures, background colour was virtually eliminated and signal strength was improved to a considerable degree. Multivariate analysis of protein profiles from the gels gave models explaining 75 to 90% of variance in sample composition. Manually deboned meat was explained to the highest degree, and with a precision of 7%. Two different qualities of mechanically recovered meat could be detected even when treated as one category. The present approach needs further refinement, but seems applicable for detecting intentional substitution of high quality meat products with low-price raw materials. One advantage of the approach is that evaluation of samples is not dependent on specific knowledge on the individual components to be analysed, so that such analytical methods are relatively easy to implement in any standard laboratory.