Electrochemical profiling using copper nanoparticle-plated electrode for identification of ostrich meat and evaluation of meat grades

Electrochemical (EC) profiling employing copper nanoparticle-plated screen-printed electrode (Cuⁿ-SPE) exhibited specific selectivity and sensitivity to peptides that could efficiently differentiate ostrich meat from pork, beef and chicken, and to evaluate grades and freshness of ostrich meat. The four meats were differentiated in 5 min by characteristic chromatographic profiles consisting only four major peaks. Peak identification by LC/MS/MS suggested that while lysine and glutamine were shown as common components, anserine were the avian-specific and carnosine was the ostrich-missing peptide in the EC profile. Statistical analysis (ROC curve) demonstrated that peak ratios could be used to evaluate ostrich meat grades with high sensitivity (up to 95%) and specificity (up to 100%). The effects of storage temperature and time were studied for potential use of Cuⁿ-SPE to evaluate meat freshness. This HPLC-EC method appeared to be superior to UV detection in terms of profile simplicity and devoid of derivatisation process or complex sample extraction procedures, rendering it a suitable method for routine rapid differentiation of ostrich meat from common meat species with the ability to simultaneously differentiate ostrich meat grades.     

Physical, Chemical, and Sensory Properties of Bologna Sausage Made with Ostrich Meat

Three formulations of bologna were prepared, differing only by the lean meat used: (1) ostrich meat from Iliofibularis muscle (fan thigh), (2) ostrich meat from Femorotibialis medius muscle (tip thigh), and (3) beef meat from Subscapularis muscle (shoulder). Physical, chemical, and sensory analyses were made. The final products formulated with ostrich meat, although having a dark appearance, were acceptable in chemical composition and other sensory characteristics. The low fat and high protein content for ostrich bolognas will help to ensure that, if marketed in sufficient quantities, ostrich meat can successfully compete with other healthy meat products. The ostrich meat (Iliofibularis muscle) formula reached the highest general quality scores in the sensory evaluation.     

Identification of pork genome in commercial meat extracts for Halal authentication by SYBR green I real‐time PCR

The identification of pork DNA in meat extracts is very important for Halal authentication and Muslim consumers demand protection from falsely labelled meat products. A pig‐specific SYBR green I real‐time PCR assay has been developed to address this issue. Using specific primers for pig mitochondrial DNA, successful amplification has been obtained by DNA extracted from control meat samples. With SYBR green I real‐time PCR, the specificity of the amplification was showed by Tm value. Detection limit of the real‐time PCR was down to 0.1 ng of porcine DNA. An appropriate linearity was obtained by construction of a standard curve based on Ct value and different concentrations of porcine DNA. By conventional PCR, no amplification was shown by porcine DNA less than 0.1 ng. The established method was conducted on commercially available meat extracts for detection and quantification of porcine DNA. The results showed the SYBR green I real‐time PCR could be considered a robust method for Halal authentication of meat extracts.     

Quality characteristics of low fat ostrich meat patties formulated with either pork lard or modified corn starch, soya isolate and water

A trained taste panel could not distinguish (P>0.05) between ostrich meat patties containing either 10% pork lard or 10% of a modified starch/protein isolate (fat replacer) mixture. The panel could distinguish between the types of ostrich muscle/meat cuts used with a significant (P<0.05) number preferring ostrich patties made from meat containing a higher collagen content (±3% vs <1%). The chemical analysis of the patties showed that within the meat classes (Class fillet-de-membraned, Class A-very lean off-cuts and Class B-off-cuts containing visual connective tissue and some fat), the patties containing the pork fat had a +6% higher total fat content than those containing the fat replacer. The fatty acid profiles of the various products were in accordance with the meat type and fat or fat replacer used. The mineral profile was as expected for lean ostrich meat that had spices added. It is concluded that fat replacers can be used successfully for the production of low fat ostrich patties without any negative quality attributes being perceived.     

Identification of hare meat by a species-specific marker of mitochondrial origin

Meat species identification in food has gained increasing interest in recent years due to public health, economic and legal concerns. Following the consumer trend towards high quality products, game meat has earned much attention. The aim of the present work was to develop a DNA-based technique able to identify hare meat. Mitochondrial cytochrome b gene was used to design species-specific primers for hare detection. The new primers proved to be highly specific to Lepus species, allowing the detection of 0.01% of hare meat in pork meat by polymerase chain reaction (PCR). A real-time PCR assay with the new intercalating EvaGreen dye was further proposed as a specific and fast tool for hare identification with increased sensitivity (1 pg) compared to end-point PCR (10 pg). It can be concluded that the proposed new primers can be used by both species-specific end-point PCR or real-time PCR to accurately authenticate hare meat.     

基于PCR多物种鉴定技术及其在肉类 鉴定中的应用

国内外的肉类掺假由来已久,法律上监管部门对此采取了严格监管措施,技术上应用了感官、显微检测和免疫学等相应的检测技术。近几年来,PCR及其衍生技术的快速发展大大推动了肉类鉴定技术的快速发展,尤其在多物种鉴定技术领域建立了如多重PCR、通用单引物多重PCR、通用引物特异性PCR和PCR-RFLP等多项技术。这些技术的发展为肉类及其制品的检测提供了重要手段,代表了检测技术领域发展的方向,但其也各有其优缺点。本文介绍了上述4种多物种鉴定技术及其在肉类鉴定中的应用,并分析了其优缺点,旨在为物种鉴定方法选择及其研究提供参考。     

Development of a Polymerase Chain Reaction System for the Detection of Dog and Cat Meat in Meat Mixtures and Animal Feed

The identification of species origin of meat represents a considerable problem for food and animal feed analysis. In the present study a PCR‐mediated method for the detection of dog and cat meat was developed. For this the cytochrome b gene sequence of both species was analyzed by restriction fragment length polymorphism (RFLP) analysis. The use of the restriction enzymes Alu I and Hae III yielded specific restriction profiles characteristic for each species. The meat of both species could additionally be differentiated with species‐specific oligonucleotide primers based on specific parts of the cytochrome b gene sequences characteristic for dog and cat. The use of these oligonucleotide primers allowed a direct identification of dog and cat meat in meat mixtures even after heat treatment.     

Refrigerated shelf life of vacuum-packaged, previously frozen ostrich meat

Previously frozen ostrich meat was evaluated over 28 days to determine the refrigerated shelf life. Intact steaks and ground meat from three ostrich carcasses were vacuum-packaged, frozen to -40°C for 5 days, and stored in a 0°C walk-in cooler. Instrumental analysis of CIE L*a*b* values indicated that ostrich meat was very dark in color, initially and over time. Microbial growth stayed slightly below 1.0 × 10(7) CFU/g for up to 21 days of refrigerated storage. Sensorially evaluated color showed an increase (p <0.05) in darkness over time. Percentage of browning increased (p<0.05) over time from 1% initially to 55% for intact steaks and 75% for ground meat by 28 days. Sensory aroma scores significantly (p<0.05) changed over time, with unacceptable aroma occurring by 14 days. Previously frozen, vacuum-packaged ostrich meat stored under refrigerated conditions should be used within 10 days.     

Species identification in meat products using real-time PCR

One of the most convenient methods for the identification of animal species in processed meat products is the examination of DNA sequences. Real-time polymerase chain reaction (qPCR) techniques are particularly suitable because even small fragments of DNA formed during heat processing of the meat can be amplified and identified. A real-time PCR method has been developed and evaluated for the identification of processed meat products. In test mixtures containing beef, pork, horse, mutton, chicken and turkey, it was possible to identify these species down to a level of 0.05%. By adjusting the number of cycles, it was possible to detect levels as low as 0.01% of these species. Cross-reactivity between these species was not found, except for pure horsemeat (250 ng DNA) in the assay for turkey meat. Cross-reactivity of deer, roe, ostrich, kangaroo, goat, domestic duck, mallard, goose, pigeon, guinea fowl, quail and pheasant was also investigated and it was found that amounts as high as 250 ng DNA of these species in the reaction vial did not result in (false) positive signals except for amounts higher than 125 ng deer DNA and higher than 50 ng pigeon DNA in the determination of chicken and beef, respectively. More than 150 meat samples were examined using DNA hybridization and real-time PCR. A comparison of the results showed a better performance of the real-time procedure compared to DNA hybridization.     

Species identification in meat products using real-time PCR.

One of the most convenient methods for the identification of animal species in processed meat products is the examination of DNA sequences. Real-time polymerase chain reaction (qPCR) techniques are particularly suitable because even small fragments of DNA formed during heat processing of the meat can be amplified and identified. A real-time PCR method has been developed and evaluated for the identification of processed meat products. In test mixtures containing beef, pork, horse, mutton, chicken and turkey, it was possible to identify these species down to a level of 0.05%. By adjusting the number of cycles, it was possible to detect levels as low as 0.01% of these species. Cross-reactivity between these species was not found, except for pure horsemeat (250 ng DNA) in the assay for turkey meat. Cross-reactivity of deer, roe, ostrich, kangaroo, goat, domestic duck, mallard, goose, pigeon, guinea fowl, quail and pheasant was also investigated and it was found that amounts as high as 250 ng DNA of these species in the reaction vial did not result in (false) positive signals except for amounts higher than 125 ng deer DNA and higher than 50 ng pigeon DNA in the determination of chicken and beef, respectively. More than 150 meat samples were examined using DNA hybridization and real-time PCR. A comparison of the results showed a better performance of the real-time procedure compared to DNA hybridization.     

Species identification in meat products using real-time PCR

One of the most convenient methods for the identification of animal species in processed meat products is the examination of DNA sequences. Real-time polymerase chain reaction (qPCR) techniques are particularly suitable because even small fragments of DNA formed during heat processing of the meat can be amplified and identified. A real-time PCR method has been developed and evaluated for the identification of processed meat products. In test mixtures containing beef, pork, horse, mutton, chicken and turkey, it was possible to identify these species down to a level of 0.05%. By adjusting the number of cycles, it was possible to detect levels as low as 0.01% of these species. Cross-reactivity between these species was not found, except for pure horsemeat (250 ng DNA) in the assay for turkey meat. Cross-reactivity of deer, roe, ostrich, kangaroo, goat, domestic duck, mallard, goose, pigeon, guinea fowl, quail and pheasant was also investigated and it was found that amounts as high as 250 ng DNA of these species in the reaction vial did not result in (false) positive signals except for amounts higher than 125 ng deer DNA and higher than 50 ng pigeon DNA in the determination of chicken and beef, respectively. More than 150 meat samples were examined using DNA hybridization and real-time PCR. A comparison of the results showed a better performance of the real-time procedure compared to DNA hybridization.     

Polymerase chain reaction assay for identification of chicken in meat and meat products

The aim of this study was to develop polymerase chain reaction (PCR) assay for specific detection of chicken meat using designed primer pair based on mitochondrial D-loop gene for amplification of 442 bp DNA fragments from fresh, processed and autoclaved meat and meat products. The PCR result was further verified by restriction digestion with HaeIII and Sau3AI enzymes for specific cutting site in amplified DNA fragments. The specificity of assay was cross tested with DNA of cattle, buffalo, sheep, goat, pig, duck, guinea fowl, turkey and quail, where amplification was observed only in chicken without cross reactivity with red meat species. However positive reaction was also observed in quail and turkey. In this study, no adverse effects of cooking and autoclaving were found on amplification of chicken DNA fragments. Thus, the detection limits was found to be less than 1% in admixed meat and meat products. The developed assay was found specific and sensitive for rapid identification of admixed chicken meat and meat products processed under different manufacturing conditions.     

Processing and nutritional characteristics of value added ostrich products

Two types of processed products, chopped hams (0.15% and 0.30% phosphate on final yield) and viennas (27 and 32% fat extension) were manufactured from ostrich fan fillets (M. iliofibularis) to determine the suitability of ostrich meat for processing purposes. Cooking losses differed significantly (P<0.10) between the two types of ham-like products (0.15% phosphate=1.59 and 0.30% phosphate=0.78%), indicating that an increase in phosphate addition reduced cooking loss. Cooking losses did not differ (P>0.10) between the two types of ostrich viennas. Colour evaluation (L (?),a (?),b (?)) of the fresh ostrich meat and processed ostrich products (chopped hams and viennas) indicated significant differences between the different types of viennas. Chemical composition (moisture, ash, protein and fat content) of the ostrich meat, processed ostrich products and similar types of commercially available products suggested that processed ostrich products can be formulated to compete successfully with similar types of products derived from other meat species.     

Lipolysis, proteolysis, physicochemical and sensory characteristics of different types of Spanish ostrich salchichon

The objective of this study was to compare three different types of salchichon: made of ostrich meat, made of ostrich meat and lean pork, and made of ostrich meat and pork belly, from physicochemical and sensory viewpoints. To evaluate the intensity of lipolysis and proteolysis produced during the ripening process, the profile and content of free fatty acids, the degree of rancidity, the non-protein, water-soluble and aminoacidic nitrogen content were determined. In addition, the composition of the fermented sausages (pH, a_w, moisture, fat, protein, ash, sodium chloride and sodium nitrite content) was analysed. From a sensory viewpoint, the organoleptic characteristics of the different types of salchichon were studied using free choice profiling. The fermented sausages had varying characteristics depending on their formulation (ostrich meat or ostrich meat plus pork) and all of them were well accepted by the panelists. This study helps characterise the different types of ostrich salchichon made in Spain.     

Quality characteristics of ostrich (Struthio camelus) burgers

Quality characteristics and storage stability of three types of burgers prepared with ostrich meat (alone or mixed with pork or beef meat) were evaluated. Burger evaluation was based on chemical, microbiological, textural, colour, sensory and oxidation characteristics. All of the assayed formulas showed acceptable general quality scores in the sensory evaluation, but the burgers formulated with 100% ostrich meat or mixing ostrich and beef meat had the highest scores. Only TBA values and redness were influenced by storage time. Burgers formulated with ostrich and pork meat had a faster oxidation rate and became more oxidized than the others. Microbial counts indicated that, at the end of the refrigerated storage (9days), all of the preparations were spoiled.     

TENDERNESS ANALYSIS AND CONSUMER SENSORY EVALUATION OF OSTRICH MEAT FROM DIFFERENT MUSCLES AND DIFFERENT AGING TIMES1

Six ostrich carcasses were split and aged for 1 h, 1 day, or 1 week, roasted to 75 C and evaluated for tenderness and sensory attributes. Shear values for aged ostrich meat were 10.1, 10.0, 10.0, and 14.1 kg/g for 1 h, 1 day, 1 week, and the beef control, respectively. The most tender ostrich muscles identified were: M. iliofibularis, M. iliofemoralis, and M. oburatorius lateralis. Tenderness was affected by fiber orientation of the meat after slicing. Shear values were higher (p<0.05) for the longitudinal fiber orientation (11.5 kg/g) compared with the transverse fiber orientation (7.4 kg/g). A 9–point hedonic scale and a consumer sensory panel were used to evaluate tenderness, flavor, and overall acceptance of selected cuts. Ostrich meat aged for 1 week provided higher (p<0.05) liking scores for flavor compared with lesser aged ostrich or the beef control. This study suggests that prepared ostrich meat provides a good alternative compared with a similar beef product.     

GNM C7-8实时荧光PCR系统对掺假肉制品中多种动物源性成分的同时检测

应用GNM C7-8实时荧光PCR系统,同时快速检测掺假肉制品中多种动物源性成分。将牛肉粉、驴肉粉、鸵鸟肉粉和羊肉粉4组不同肉粉中分别混入猪肉粉、鸭肉粉、马肉粉、鸡肉粉和狐狸肉粉中的2~3种肉粉,制备人工模拟掺假肉制品。通过GNM C7-8实时荧光PCR和ABI7500荧光PCR方法,对上述四种掺假肉制品进行多种动物源性成分检测和比较。结果表明,GNM C7-8实时荧光PCR方法与ABI7500荧光PCR方法从掺假肉制品中检测猪、鸭、马、鸡和狐狸5种成分的循环数一致,分别是31、31、29、32和25,但基于八模块设计的GNM C7-8实时荧光PCR方法能同时检测四种掺假肉制品中不同动物源性成分,检测时间更短。因此,GNM C7-8实时荧光PCR系统的八个模块能够独立运行,互不干扰,无交叉污染,能够实现对掺假肉制品中多种动物源性成分的同时快速检测,为肉制品掺假检测提供强有力的方法支持。     

Ostrich meat: Physico-chemical characteristics and comparison with turkey and bovine meat

In several European countries ostrich breeding has now become quite common. In Italy this has also given rise to the need for regulations for the slaughtering of Ratites. The present work studies and compares the physico-chemical characteristics of the meat from the thigh of the ostrich with the same anatomical cuts of turkey and bovine. The ostrich meat muscle of the thigh was imported vacuum packed from Israel and France, the muscles considered were m. flexor cruris and m. iliofibularis. The turkey thighs were from the domestic market (supermarket) and the bovine muscle m. pectineus was from spent milking animals from an EEC slaughterhouse. Needless to say that the breeding, the feeding and the system of slaughtering could influence some parameters of the different kinds of meat; however these factors could not be assessed. Due to its tenderness, low fat content and cholesterol levels ostrich meat is, in accordance with modern-day nutritional principles, a valid alternative to other kinds of meat.     

PCR方法快速鉴别食品中肉的种类

本文针对食品中肉成分种类鉴别开发了一种快速灵敏的PCR检测方法,可检测食品中是否存在猪肉、牛肉、羊肉以及鸡肉等成分。采用微波助提法提取样品中DNA,简化了前处理步骤,可在短时间内完成从多种不同类型肉与肉制品中提取肉成分DNA。为了评价方法的可靠性与灵敏度,猪肉以及掺入了不同比例浓度猪肉成分的食品样品采用本方法进行了核酸提取与PCR分析。检测结果表明,方法可检测出低至含有0.5%浓度的猪肉成分的混合样品。随机抽取50份不同类型的市面食品样品,检测出5份食品含有猪肉成分,7份食品中含有牛肉成分,5份食品中含有羊肉成分。该样品前处理方法、DNA提取方法以及PCR检测方法可广泛应用于食品中肉成分种类的检测鉴别。