The detection of commercial duck species in food using a single probe-multiple species-specific primer real-time PCR assay

An effective analytical droplet digital PCR approach for identification and quantification of fur-bearing animal meat in raw and processed food

Available nuclear gene sequences for meat detection are still rare and little applicability in the investigation of new types of meat adulteration such as fox, mink and raccoon dog was performed. In the present work, we developed a reliable qualitative and quantitative detection method for fur-bearing animal meat based on droplet digital PCR (ddPCR). Three sets of primers and probes targeted nuclear genes for fox, mink and raccoon dog were designed for ddPCR system; In addition, turkey was selected as internal reference to transform the copy numbers to the fraction of target species. Results indicated that the dynamic ranges of three fur-bearing animals were all from 1% to 90%; the limit of detection (LOD) and limit of quantification (LOQ) for three fur-bearing animals were same, with LOD 0.1% (w/w) and LOQ 1% (w/w). Moreover, we confirmed that different additives had no effect on quantification accuracy in the ddPCR assay.

Designing a time-effective TaqMan probe-based real-time polymerase chain reaction protocol for the identification of Yersinia enterocolitica in raw pork meat

The aim of this study was to design a time-effective method comprising a short pre-enrichment step in a non-selective broth in combination with the TaqMan probe applied in the real-time polymerase chain reaction to detectYersinia enterocoliticastrains in raw pork meat. The method enabled to detect 1 colony forming unit per 25 mg ofYersinia enterocoliticain pork meat. The specificity and reliability of the method was not diminished by the company of microflora naturally present in meat. The method was found successful to detect pathogenicYersinia enterocoliticastrains in pork meat. It is advised to be used for assessing the microbial risk and for controlling the microbial quality of meat and meat products.

Cross priming amplification with nucleic acid test strip analysis of mutton in meat mixtures

A simple, sensitive, accurate and affordable rapid detection of meat species authentication is urgently needed in food industry. In this study, a cross priming amplification (CPA) combining nucleic acid test strip (CPA-Strip) assay for rapid detection of mutton from meat mixture were developed and its feasibility was investigated. In an isothermal CPA system, cytochrome b (cytb) gene as target was amplified at 63°C for 60min. The nucleic acid strip was able to show the corresponding test line in the presence of target gens in 5min. Non-targeting gene interference was not evident. The CPA-Strip has been applied for the detection of 0.1-100% mutton in a thermal treated meat mixtures with a detection limit of a detect limit of 1%. CPA-Strip assay would be a promising simple, rapid and sensitive method for identification of target species in raw and processed meat mixtures.

On-site identification of meat species in processed foods by a rapid real-time polymerase chain reaction system

Correct labeling of foods is critical for consumers who wish to avoid a specific meat species for religious or cultural reasons. Therefore, gene-based point-of-care food analysis by real-time Polymerase Chain Reaction (PCR) is expected to contribute to the quality control in the food industry. In this study, we perform rapid identification of meat species by our portable rapid real-time PCR system, following a very simple DNA extraction method. Applying these techniques, we correctly identified beef, pork, chicken, rabbit, horse, and mutton in processed foods in 20min. Our system was sensitive enough to detect the interfusion of about 0.1% chicken egg-derived DNA in a processed food sample. Our rapid real-time PCR system is expected to contribute to the quality control in food industries because it can be applied for the identification of meat species, and future applications can expand its functionality to the detection of genetically modified organisms or mutations.

A nuclear DNA-based species determination and DNA quantification assay for common poultry species

DNA testing for food authentication and quality control requires sensitive species-specific quantification of nuclear DNA from complex and unknown biological sources. We have developed a multiplex assay based on TaqMan® real-time quantitative PCR (qPCR) for species-specific detection and quantification of chicken (Gallus gallus), duck (Anas platyrhynchos), and turkey (Meleagris gallopavo) nuclear DNA. The multiplex assay is able to accurately detect very low quantities of species-specific DNA from single or multispecies sample mixtures; its minimum effective quantification range is 5 to 50 pg of starting DNA material. In addition to its use in food fraudulence cases, we have validated the assay using simulated forensic sample conditions to demonstrate its utility in forensic investigations. Despite treatment with potent inhibitors such as hematin and humic acid, and degradation of template DNA by DNase, the assay was still able to robustly detect and quantify DNA from each of the three poultry species in mixed samples. The efficient species determination and accurate DNA quantification will help reduce fraudulent food labeling and facilitate downstream DNA analysis for genetic identification and traceability.

Detection of chicken and turkey meat in meat mixtures by using real-time PCR assays

In this study, TaqMan-based real-time Polymerase Chain Reaction (PCR) techniques were developed for the detection of chicken and turkey meat in raw and heat-treated meat mixtures. Primers and TaqMan probe sets were designed to amplify 86 bp and 136 bp fragments for the chicken and turkey species, respectively, on the mitochondrial NADH dehydrogenase subunit 2 gene. In the results, it was possible to detect each species at the level of 0.1 pg template DNA with the TaqMan probe technique without any cross-reactivity with nontarget species (bovine, ovine, donkey, pork, and horse) while the detection level was 1 pg template DNA using conventional PCR. The TaqMan probe assays used in this study allowed the detection of as little as 0.001% level of both species in the experimental meat mixtures, prepared by mixing chicken and turkey meat with beef at different levels (0.001% to 10%). In conclusion, TaqMan probe assays developed in this research are promising tools in the specific identification and sensitive quantification of meat species even in the case of heat-treated meat products, and suitable for a rapid, automated, and routine analysis.

Authentication of meat and meat products

In recent years, interest in meat authenticity has increased. Many consumers are concerned about the meat they eat and accurate labelling is important to inform consumer choice. Authentication methods can be categorised into the areas where fraud is most likely to occur: meat origin, meat substitution, meat processing treatment and non-meat ingredient addition. Within each area the possibilities for fraud can be subcategorised as follows: meat origin-sex, meat cuts, breed, feed intake, slaughter age, wild versus farmed meat, organic versus conventional meat, and geographic origin; meat substitution-meat species, fat, and protein; meat processing treatment-irradiation, fresh versus thawed meat and meat preparation; non-meat ingredient addition-additives and water. Analytical methods used in authentication are as diverse as the authentication problems, and include a diverse range of equipment and techniques. This review is intended to provide an overview of the possible analytical methods available for meat and meat products authentication. In areas where no authentication methods have been published, possible strategies are suggested.

Polymerase chain reaction assay for verifying the labeling of meat and commercial meat products from game birds targeting specific sequences from the mitochondrial D-loop region

A PCR assay was developed for the identification of meats and commercial meat products from quail (Coturnix coturnix), pheasant (Phasianus colchicus), partridge (Alectoris spp.), guinea fowl (Numida meleagris), pigeon (Columba spp.), Eurasian woodcock (Scolopax rusticola), and song thrush (Turdus philomelos) based on oligonucleotide primers targeting specific sequences from the mitochondrial D-loop region. The primers designed generated specific fragments of 96, 100, 104, 106, 147, 127, and 154 bp in length for quail, pheasant, partridge, guinea fowl, pigeon, Eurasian woodcock, and song thrush tissues, respectively. The specificity of each primer pair was tested against DNA from various game and domestic species. In this work, satisfactory amplification was accomplished in the analysis of experimentally pasteurized (72 degrees C for 30 min) and sterilized (121 degrees C for 20 min) meats, as well as in commercial meat products from the target species. The technique was also applied to raw and sterilized muscular binary mixtures, with a detection limit of 0.1% (wt/wt) for each of the targeted species. The proposed PCR assay represents a rapid and straightforward method for the detection of possible mislabeling in game bird meat products.

Identification of European Hake species (Merluccius merluccius) using real-time PCR

A rapid and precise method for identifying European hake (Merluccius merluccius) based on TaqMan technology is presented. The method can be applied to fresh, frozen, and processed fish products to detect the fraudulent or unintentional mislabeling of this species. Specific primers and a minor groove binding (MGB) TaqMan probe were designed for this purpose based on partial sequences of the mitochondrial DNA control region. Combinations of primers and probe concentrations that gave the lowest Ct value and the highest final fluorescence value were selected to carry out efficiency, specificity, and cross-reactivity assays. The method was successfully tested on 31 commercial hake samples. A Ct value of about 16 was obtained when Merluccius merluccius was present; however, the fluorescence signal was not detected most of the time (Ct value 40) or presented significantly higher Ct values (38.2 +/- 0.96) for the nonhake species.