Technical note: Detection of cat, dog, and rat or mouse tissues in food and animal feed using species-specific polymerase chain reaction

Single tube multiplex PCR assay for the identification of banned meat species

Food adulteration has a direct impact on public health, religious faith, fair-trades, and wildlife. In the present study, a reliable and sensitive assay has been developed for verifying meat adulteration in food chain. The multiplex PCR system was optimised for identification of chicken, cow/buffalo, sheep/goat, horse/donkey, pork, and dog DNAs in a single reaction mixture simultaneously. The primers were designed using 12 S rRNA gene sequences with fragment size in the range of 113 bp to 800 bp, which can be easily visualised on agarose gel electrophoresis making the technique economical. After validation of accuracy, specificity, and sensitivity, commercially available meat products (n = 190) were screened, comprising both raw and cooked meat samples. The results demonstrated a high rate of adulteration (54.5%) in meat products. The technique developed here can be easily used for screening of different meat products for export and import purposes as well as for food inspection and livestock diagnostic laboratories.

Screening of commercial meat products from supermarket chains for feline derivatives using SP-PCR-RLFP and lab-on-a-chip

Determination of feline meat in food products is an important issue for social, health, economic and religious concern. Hence this paper documented the application of species specific polymerase chain reaction-restriction fragment length polymorphism (SP-PCR-RFLP) assay targeting a short-fragments (69 bp) of mitochondrial cytochrome b (cytb) gene to screen feline meat in commercial meat products using lab-on-a-chip. The SP-PCR assay proved its specificity theoretically and experimentally while testing with different common animal, aquatic and plant species of DNA. The feline specific (69 bp, 43- and 26-bp) characteristic molecular DNA pattern was observed by SP-PCR and RFLP analysis. For assay performance, it was tested in three different types of commercial dummy meat products such as frankfurters, nuggets and meatballs and digested with AluI-restriction enzyme. The highest sensitivity of the assay using lab-on-a-chip was as low as 0.1 pg or 0.01 % (w/w) in commercial dummy meat products. We have also applied this assay to screen three important commercial meat products of six different brand from six supermarket chains located at three different states of Malaysia. Thus total 378 samples were tested to validate the specificity, sensitivity, stability of the assay and utilization of it for commercial meat product screening.

A simple and sensitive two-tube multiplex PCR assay for simultaneous detection of ten meat species

A sensitive and reliable technique for meat species identification is required to prevent food adulteration, particularly in meat production. This work developed an optimized multiplex PCR assay for simultaneous identification of five commonly consumed and five commonly banned meat species in meat products. We designed primers that specifically amplified mitochondrial ATPase subunit 8 gene regions of different lengths of bovine, ovine, swine, chicken, turkey, cat, dog, mouse and human DNAs. The developed multiplex PCR assay proved to be specific, sensitive down to 30pg DNA per reaction, reproducible and economical. It could be used with a variety of raw meats and processed food samples and is easily applicable in a routine laboratory analysis without specific sophisticated equipment.

Sequence analysis of ABO and its homologues is valid for species identification

BACKGROUND

ABO and its paralogues, such as A3GALT2 and GGTA1, encoding α1,3-Gal(NAc) transferases, belong to the glycosyltransferase 6 (GT6) gene family. We have developed an alternative method for the identification of species based on sequence variations within the GT6 gene family, which is applicable to degraded DNA.

METHODS/MATERIALS

DNA samples prepared from control mammalian species, together with an unknown sample, were polymerase chain reaction (PCR)-amplified using one universal primer pair targeting the sequences in the last coding exons of the GT6 gene family, yielding 141-bp products derived from those multiple loci. After cloning, sequence determination and Basic Local Alignment Search Tool analysis, phylogenetic trees were constructed.

RESULTS

Comparison of the sequences obtained with those references showed good concordance with each of the starting species of mammals. This system was able to identify 'mouse' or 'rodent' as the origin of the unknown sample.

CONCLUSION

For the identification of species, genotyping of ABO and its homologues would be applicable for the analysis of degraded DNA samples. Although the method employed in this study is likely valid for mammals, it would not be suitable for birds, fish and reptiles. It may be possible to improve the present method for use with other species by employing an alternative universal primer set.

Serological Evidence of Rickettsia spp. in Western Australian Dogs

It has been claimed that dogs can be useful sentinels for public health monitoring of vector-borne infectious diseases, including Rickettsia spp. We used 153 canine blood samples opportunistically collected at Murdoch University Veterinary Hospital and 156 canine sera collected from Aboriginal communities in northwest Western Australia to test for evidence of Rickettsia spp. exposure, using microimmunofluorescence (MIF) in the latter case, and both MIF and polymerase chain reaction (PCR) in the former. Conventional and real-time PCR failed to amplify any Rickettsia spp. DNA. The seroprevalence for spotted fever group/transitional group Rickettsia spp. in Western Australian dogs was 17.3% (54/312), and for typhus group (TG) Rickettsia spp., 18.4% (57/310), with a cut-off titer of 1:128. Young dogs (≤ 2 years) from Aboriginal communities had significantly lower seropositivity to TG Rickettsia spp. compared with all other groups, and young Perth dogs had a significantly higher seropositivity to TG Rickettsia spp. than all Aboriginal community dogs.

An Updated Review of Meat Authenticity Methods and Applications

Adulteration of foods is a serious economic problem concerning most foodstuffs, and in particular meat products. Since high-priced meat demand premium prices, producers of meat-based products might be tempted to blend these products with lower cost meat. Moreover, the labeled meat contents may not be met. Both types of adulteration are difficult to detect and lead to deterioration of product quality. For the consumer, it is of outmost importance to guarantee both authenticity and compliance with product labeling. The purpose of this article is to review the state of the art of meat authenticity with analytical and immunochemical methods with the focus on the issue of geographic origin and sensory characteristics. This review is also intended to provide an overview of the various currently applied statistical analyses (multivariate analysis (MAV), such as principal component analysis, discriminant analysis, cluster analysis, etc.) and their effectiveness for meat authenticity.

TaqMan probe real-time polymerase chain reaction assay for the quantification of canine DNA in chicken nugget

This paper describes a short-amplicon-based TaqMan probe quantitative real-time PCR (qPCR) assay for the quantitative detection of canine meat in chicken nuggets, which are very popular across the world, including Malaysia. The assay targeted a 100-bp fragment of canine cytb gene using a canine-specific primer and TaqMan probe. Specificity against 10 different animals and plants species demonstrated threshold cycles (Ct) of 16.13 ± 0.12 to 16.25 ± 0.23 for canine DNA and negative results for the others in a 40-cycle reaction. The assay was tested for the quantification of up to 0.01% canine meat in deliberately spiked chicken nuggets with 99.7% PCR efficiency and 0.995 correlation coefficient. The analysis of the actual and qPCR predicted values showed a high recovery rate (from 87% ± 28% to 112% ± 19%) with a linear regression close to unity (R(2) = 0.999). Finally, samples of three halal-branded commercial chicken nuggets collected from different Malaysian outlets were screened for canine meat, but no contamination was demonstrated.

Evaluation of a new recombinant oncolytic vaccinia virus strain GLV-5b451 for feline mammary carcinoma therapy

Virotherapy on the basis of oncolytic vaccinia virus (VACV) infection is a promising approach for cancer therapy. In this study we describe the establishment of a new preclinical model of feline mammary carcinoma (FMC) using a recently established cancer cell line, DT09/06. In addition, we evaluated a recombinant vaccinia virus strain, GLV-5b451, expressing the anti-vascular endothelial growth factor (VEGF) single-chain antibody (scAb) GLAF-2 as an oncolytic agent against FMC. Cell culture data demonstrate that GLV-5b451 virus efficiently infected, replicated in and destroyed DT09/06 cancer cells. In the selected xenografts of FMC, a single systemic administration of GLV-5b451 led to significant inhibition of tumor growth in comparison to untreated tumor-bearing mice. Furthermore, tumor-specific virus infection led to overproduction of functional scAb GLAF-2, which caused drastic reduction of intratumoral VEGF levels and inhibition of angiogenesis.

In summary, here we have shown, for the first time, that the vaccinia virus strains and especially GLV-5b451 have great potential for effective treatment of FMC in animal model.

Species identification through mitochondrial rRNA genetic analysis

Inter-species and intraspecific variations in mitochondrial DNA (mtDNA) were observed in a bioinformatics analysis of the mitochondrial genomic sequences of 11 animal species. Some highly conserved regions were identified in the mitochondrial 12S and 16S ribosomal RNA (rRNA) genes of these species. To test whether these sequences are universally conserved, primers were designed to target the conserved regions of these two genes and were used to amplify DNA from 21 animal tissues, including two of unknown origin. By sequencing these PCR amplicons and aligning the sequences to a database of non-redundant nucleotide sequences, it was confirmed that these amplicons aligned specifically to mtDNA sequences from the expected species of origin. This molecular technique, when combined with bioinformatics, provides a reliable method for the taxonomic classification of animal tissues.

Use of PCR-based assays for the detection of the adventitious agent porcine circovirus type 1 (PCV1) in vaccines, and for confirming the identity of cell substrates and viruses used in vaccine production

Safety and quality are important issues for vaccines. Whereas reversion to virulence poses a safety risk with live attenuated vaccines, the potential for the presence of adventitious agents is also an issue of vaccine quality. The recent detection or porcine circovirus type 1 (PCV1) in human vaccines has further highlighted the importance of quality control in vaccine production. The purpose of this study was to use a novel conventional PCR to detect PCV1, and subsequently screen materials used in the manufacture of vaccines at Bharat Biotech International Limited, India. The genome or gene fragments of PCV1 were not detected in any of the vaccines and materials tested, including the live attenuated rotavirus vaccine candidate ROTAVAC(®). Further, the identity of the cells and the viruses used as starting materials in the manufacture of these vaccines was confirmed by species-specific PCR or virus-specific RT-PCR, and no cross-contamination was detected in any case. The methods can be applied for regular in-house quality control screening of raw materials and seeds/banks, as well as formulated vaccines.

Using species-specific repeat and PCR-RFLP in typing of DNA derived from blood of human and animal species

Species determination of tissue specimens, including blood, is an important component of forensic analysis to distinguish human from animal remains. DNA markers based on a method of species-specific PCR and amplifying the 359-base pair (bp) fragment of the mitochondrially encoded cytochrome-b gene and then digestion with the TaqI restriction enzyme were developed for detection and discrimination of human, cattle, buffalo, horse, sheep, pig, dog, cat and chicken blood samples. The results reveal that PCR-amplification of the gene encoding the species-specific repeat (SSR) region generated 603 bp in cattle and buffalo, 221 bp in horse, 374 bp in sheep, <or=100 bp in pig, 808 bp in dog, 672 bp in cat and 50 bp in chicken. Restriction analysis of the amplified 359-bp portion of the cytochrome-b gene using the TaqI restriction enzyme results in species-specific restriction fragment length polymorphism (RFLP) between buffalo, cattle and human. Two different bands were generated in buffalo (191 and 168 bp) and human (209 and 150 bp), with no digestion in cattle (359 bp). Cytochrome-b is a highly conserved region and consequently a good molecular marker for diagnostic studies. Therefore, the two complementary techniques, SSR-PCR and PCR-RFLP, could be used successfully as routine methods in forensics for sensitive, rapid, simple and inexpensive identification of the species in bloodstains.