A highly sensitive and specific tetraplex PCR assay for soybean, poultry, horse and pork species identification in sausages: development and validation

Heat-Treated Meat Origin Tracing and Authenticity through a Practical Multiplex Polymerase Chain Reaction Approach

Meat adulteration have become a global issue, which has increasingly raised concerns due to not only economic losses and religious issues, but also public safety and its negative effects on human health. Using optimal primers for seven target species, a multiplex PCR method was developed for the molecular authentication of camel, cattle, dog, pig, chicken, sheep and duck in one tube reaction. Species-specific amplification from the premixed total DNA of seven species was corroborated by DNA sequencing. The limit of detection (LOD) is as low as 0.025 ng DNA for the simultaneous identification of seven species in both raw and heat-processed meat or target meat: as little as 0.1% (w/w) of the total meat weight. This method is strongly reproducible even while exposed to intensively heat-processed meat and meat mixtures, which renders it able to trace meat origins in real-world foodstuffs based on the authenticity assessment of commercial meat samples. Therefore, this method is a powerful tool for the inspection of meat adulterants and has broad application prospects.

Current Analytical Methods and Research Trends Are Used to Identify Domestic Pig and Wild Boar DNA in Meat and Meat Products

The pig, one of the most important livestock species, is a meaningful source of global meat production. It is necessary, however, to prove whether a food product that a discerning customer selects in a store is actually made from pork or venison, or does not contain it at all. The problem of food authenticity is widespread worldwide, and cases of meat adulteration have accelerated the development of food and the identification methods of feed species. It is worth noting that several different molecular biology techniques can identify a porcine component. However, the precise differentiation between wild boar and a domestic pig in meat products is still challenging. This paper presents the current state of knowledge concerning the species identification of the domestic pig and wild boar DNA in meat and its products.

Detection and characterization of meat adulteration in various types of meat products by using a high-efficiency multiplex polymerase chain reaction technique

Identification of meat authenticity is a matter of increasing concerns due to religious, economical, legal, and public health reasons. However, little is known about the inspection of eight meat species in one tube reaction due to technological challenge of multiplex polymerase chain reaction (PCR) techniques. Here, a developed multiplex PCR method can simultaneously authenticate eight meat species including ostrich (753 bp), cat (564 bp), goose (391 bp), duck (347 bp), chicken (268 bp), horse (227 bp), dog (190 bp), and sheep (131 bp). The detectable deoxyribonucleic acid (DNA) contents for each target species was as low as 0.01 ng in both raw and heat-treated meat or target meat down to 0.1% (w/w) of total meat weight reflecting high stability of the assay in heat processing condition, indicating that this method is adequate for tracing meat origin in real-world meat products, which has been further validated by authenticity assays of commercial meat products. Overall, this method is a powerful tool for accurate evaluation of meat origin with a good application foreground.

A Heptaplex PCR Assay for Molecular Traceability of Species Origin With High Efficiency and Practicality in Both Raw and Heat Processing Meat Materials

Frequent meat frauds have become a global issue because adulteration risks the food safety, breaches market rules, and even threatens public health. Multiplex PCR is considered to be a simple, fast, and inexpensive technique that can be applied for the identification of meat products in food industries. However, relatively less is known about a multiplex PCR method authenticating seven animal species simultaneously in one reaction due to technological challenge. Through screening new species-specific primers and optimizing PCR system, a heptaplex PCR method was established, which could simultaneously detect seven meat ingredients of camel (128 bp), pigeon (157 bp), chicken (220 bp), duck (272 bp), horse (314 bp), beef (434 bp), and pork (502 bp) in a single-tube reaction. DNA sequencing solidly validated that each set of primers specifically amplified target species from total DNA mixtures of seven meat species. The developed multiplex assay was stable and sensitive enough to detect 0.01–0.025 ng DNA from various meat treatments including raw, boiled, and autoclaved meat samples or target meat content of 0.1% total meat weight, suggesting the suitability of the heptaplex PCR technique for tracing target meats with high accuracy and precision. Most importantly, a market survey validated the availability of this multiplex PCR technique in real-world meat products with a good application foreground.

A Simple and Reliable Single Tube Septuple PCR Assay for Simultaneous Identification of Seven Meat Species

Multiplex PCR methods have been frequently used for authentication of meat product adulteration. Through screening of new species-specific primers designed based on the mitochondrial DNA sequences, a septuple PCR method is ultimately developed and optimized to simultaneously detect seven species including turkey (110 bp), goose (194 bp), pig (254 bp), sheep (329 bp), beef (473 bp), chicken (612 bp) and duck (718 bp) in one reaction. The proposed method has been validated to be specific, sensitive, robust and inexpensive. Taken together, the developed septuple PCR assay is reliable and efficient, not only to authenticate animal species in commercial meat products, but also easily feasible in a general laboratory without special infrastructures.

Rapid discrimination of intact beef, venison and lamb meat using Raman spectroscopy

With increasing demand for fast and reliable techniques for intact meat discrimination, we explore the potential of Raman spectroscopy in combination with three chemometric techniques to discriminate beef, lamb and venison meat samples. Ninety (90) intact red meat samples were measured using Raman spectroscopy, with the acquired spectral data preprocessed using a combination of rubber-band baseline correction, Savitzky-Golay smoothing and standard normal variate transformation. PLSDA and SVM classification were utilized in building classification models for the meat discrimination, whereas PCA was used for exploratory studies. Results obtained using linear and non-linear kernel SVM models yielded sensitivities of over 87 and 90 % respectively, with the corresponding specificities above 88 % on validation against a test set. The PLSDA model yielded over 80 % accuracy in classifying each of the meat specie. PLSDA and SVM classification models in combination with Raman spectroscopy posit an effective technique for red meat discrimination.

Current analytical methods for porcine identification in meat and meat products

Authentication of meat products is critical in the food industry. Meat adulteration may lead to religious apprehensions, financial gain and food-toxicities such as meat allergies. Thus, empirical validation of the quality and constituents of meat is paramount. Various analytical methods often based on protein or DNA measurements are utilized to identify meat species. Protein-based methods, including electrophoretic and immunological techniques, are at times unsuitable for discriminating closely related species. Most of these methods have been replaced by more accurate and sensitive detection methods, such as DNA-based techniques. Emerging technologies like DNA barcoding and mass spectrometry are still in their infancy when it comes to their utilization in meat detection. Gold nanobiosensors have shown some promise in this regard. However, its applicability in small scale industries is distant. This article comprehensively reviews the recent developments in the field of analytical methods used for porcine identification.

Monitoring of sausage products sold in Sichuan Province, China: a first comprehensive report on meat species' authenticity determination

Presently, there is growing concern worldwide regarding the adulteration of meat products. However, no reports on determining meat authenticity have been reported in China. To verify labelling compliance and evaluate the existence of fraudulent practices, 250 sausage samples were purchased from local markets in Sichuan Province and analysed for the presence of chicken, pork, beef, duck and genetically modified soybean DNA using real-time and end-point PCR methods, providing a Chinese case study on the problem of world food safety. In total, 74.4% (186) of the samples were properly labelled, while the other 25.6% (64) were potentially adulterated samples, which involved three illicit practices: product removal, addition and substitution. The most common mislabelling was the illegal addition of, or contamination with, duck. Therefore, meat authenticity monitoring should be routinely conducted. Additionally, the strict implementation of the nation’s food safety laws, along with regular surveillance, should be compulsory to alleviate and deter meat adulteration.

A sensitive multiplex PCR protocol for simultaneous detection of chicken, duck, and pork in beef samples

A rapid and sensitive multiplex PCR assay was developed for simultaneous identification of the adulteration ingredients of chicken, duck and pork in beef. Specific primers for the mitochondrial genes of Cyt b, CO III, ATPase subunit 8/6 and Cyt b of chicken, duck, pork, and beef, respectively, were adopted in the assay. DNA exaction from meat samples was carried out by using magnetic nanoparticles as rapid separation substrates. The multiplex PCR assay showed that the limit of detection was 0.05% for each species. Moreover, the multiplex PCR specifically identified five beef samples adulterated with pork and one beef samples adulterated with chicken among the 35 commercial samples examined, indicating the practicability of this multiplex PCR method for identifying adulterated ingredients of chicken, duck, and pork in commercial beef products.

Evaluation of compost, vegetable and food waste as amendments to improve the composting of NaOH/NaClO-contaminated poultry manure

Regular usage of NaOH/NaClO disinfectants results in high sodium salt and alkalinity of poultry manure. This study compared three amendments: vegetable waste (V), food waste (F) and mature compost (C) for their ability to improve the composting of NaOH/NaClO-contaminated poultry manure. C compost resulted in the highest compost temperatures (p<0.001) and greatest reduction in OM, TC, TN and NH₄-N (p<0.05). C and V composts were more efficient at lowering extractable-Na (ext-Na) and electrical conductivity (EC) than F (p<0.05). Maturity was primarily indicated by NH₄-N, EC and ext-Na. Bacterial dynamics was profoundly influenced by NH₄-N, EC and TC, with the decrease leading to discriminate genera shift from Sinibacillus and Thiopseudomonas to Brevbacterium, Brachybacterium, and Microbacterium. These findings suggest that mature compost was more desirable amendment than vegetable and food waste in the composting of NaOH/NaClO-contaminated poultry manure, and the decrease of ext-Na indicated compost maturity but did not influence bacterial dynamics.

Detection of allergenic additives in processed meat products

Allergic responses to food components are an increasing problem all over the world. It is therefore important to protect people who are vulnerable to food allergens against accidental and unintended consumption of products containing allergic ingredients. The meat industry commonly uses various allergic additives in the production of processed products, such as legumes (soy, peas, beans), milk and egg preparations, cereals containing gluten (wheat, rye, barley and oats), and spices (celery and mustard). These meat additives have specific technological properties, which help to create a texture or flavor profile, or affect the nutritional value, although some of them, such as soy, mustard, milk and egg white proteins, can cause severe allergic reactions. The aim of this paper is to discuss the application of various recently established methods of detection of allergenic additives in processed meat products - for instance cold cuts and sausages. The new methods are based mainly on protein, DNA, and isoflavones or phytic acid analysis. The article also characterizes the latest trends in the development of research on methods that would enable quick and reliable identification of targeted allergens in meat products. © 2018 Society of Chemical Industry.

Development and validation of a universal primer pair for the simultaneous detection of eight animal species

In the present study, we developed a novel simplex PCR assay for the simultaneous detection of eight animal species, including goat, sheep, deer, buffalo, cattle, yak, pig and camel. A unique pair of universal primers was designed to target mitochondrial DNA variable regions in the eight animal species, generating, 787, 763, 563, 512, 507, 491, 455 and 385bp long fragments for goat, sheep, deer, buffalo, cattle, yak, pig and camel, respectively. The assay showed no cross-reactivity with other common domestic animals, and was validated by sequencing and enzyme digestion. Detection limit for DNA samples from the eight animal species varied between 6 and 20pg in a 20μl PCR mixture. Interestingly, the newly developed method successfully identified 170 commercial meat products, and is simple, fast, sensitive, specific, and cost-effective. Therefore, it could be used for the detection of goat, sheep, deer, buffalo, cattle, yak, pig, and camel species in foodstuffs.

Double Gene Targeting Multiplex Polymerase Chain Reaction-Restriction Fragment Length Polymorphism Assay Discriminates Beef, Buffalo, and Pork Substitution in Frankfurter Products

Beef, buffalo, and pork adulteration in the food chain is an emerging and sensitive issue. Current molecular techniques to authenticate these species depend on polymerase chain reaction (PCR) assays involving long and single targets which break down under natural decomposition and/or processing treatments. This novel multiplex polymerase chain reaction-restriction fragment length polymorphism assay targeted two different gene sites for each of the bovine, buffalo, and porcine materials. This authentication ensured better security, first through a complementation approach because it is highly unlikely that both sites will be missing under compromised states, and second through molecular fingerprints. Mitochondrial cytochrome b and ND5 genes were targeted, and all targets (73, 90, 106, 120, 138, and 146 bp) were stable under extreme boiling and autoclaving treatments. Target specificity and authenticity were ensured through cross-amplification reaction and restriction digestion of PCR products with AluI, EciI, FatI, and CviKI-1 enzymes. A survey of Malaysian frankfurter products revealed rampant substitution of beef with buffalo but purity in porcine materials.

The development of a hexaplex-conventional PCR for identification of six animal and plant species in foodstuffs

A hexaplex-conventional PCR assay was developed for identification of five meat and one plant species origins in foodstuffs simultaneously. The method merges the use of horse (Equus caballus), soybean (Glycine max), sheep (Ovis aries), poultry (Meleagris meleagris), pork (Sus scrofa), and cow (Bos taurus) specific primers that amplify fragments (horse; 85 bp, soybean; 100 bp, sheep; 119 bp, poultry; 183 bp, pork; 212 bp and cow; 271 bp) of the mitochondrial cyt b, lectin, 12S rRNA, 12S rRNA, ATPase subunit 6 genes and ATPase subunit 8 genes respectively, and a universal 18S rRNA primers that amplifies a 141 bp. Multiplex analysis of the reference food samples showed that detection limit of the hexaplex assay was 0.01% for each species. Taken together, all data indicated that this hexaplex PCR assay was a simple, fast, sensitive, specific, and cost-effective detection method for horse, soybean, sheep, poultry, pork and cow species in foodstuffs.

Development of qualitative and quantitative PCR analysis for meat adulteration from RNA samples

Total RNA samples were used to establish qualitative and quantitative PCR-based methods for assessing meat adulteration. The primers were designed based on the mRNA sequences of troponin I (TnI), mitochondrial ribosomal protein (MRP) and tropomodulin genes to distinguish chicken, pork, goat, beef and ostrich. There was no cross reaction between the primers, and the detection limit of the cDNA template was 0.01 and 20 ng in simplex PCR and multiplex PCR, respectively. In the low temperature storage test, the detection limits of cDNA template with 10 and 1 ng were determined at 4 °C and -80 °C. In quantitative assay, the precision of real-time PCR analysis expressed as a coefficient of variation (CV) ranged from 0.25% to 5.24% and the trueness, expressed as an error, ranged from 0.28% to 6.98% for adulteration. Thus, herein, we provided alternative tools for the assessment of meat adulteration using mRNA-based PCR methods.

Species Authentication of Common Meat Based on PCR Analysis of the Mitochondrial COI Gene

Adulteration of meat products and costly animal-derived commodities with their inferior/cheaper counterparts is a grievous global problem. Species authentication is still technical challenging, especially to those deep processed products. The present study described the design of seven sets of species-specific primer based on a high heterozygous region of mitochondrial cytochrome c oxidase subunit I (COI) gene. These primers were proven to have high species specificity and no cross-reactions and unexpected products to different DNA source. Multiplex PCR assay was achieved for rapid and economical identification of four commonly consumed meats (pork, beef, chicken, and mutton). The conventional PCR assay was sensitive down to 0.001 ng of DNA template in the reactant. The developed method was also powerful in detecting as low as 0.1-mg adulterated pork (0.05 % in wt/wt) in an artificial counterfeited mutton. Validation test showed that the assay is specific, reproducible, and robust in commercial deep processed meats, leatherware, and feather commodities. This proposed method will be greatly beneficial to the consumers, food industry, leather, and feather commodity manufacture.