The species identification of bovine, porcine, ovine and chicken components in animal meals, feeds and their ingredients, based on COX I analysis and ribosomal DNA sequences

Development and validation of a universal primer pair for the taxonomic and phylogenetic studies of vertebrates

BACKGROUND

Recent studies in the field of molecular identification have described 16S rRNA gene as a highly informative fragment of mitochondrial DNA for species discrimination. This study presents a newly developed universal primer pair yielding an approximately 350 bp fragment of mitochondrial 16S rRNA, variable enough to encompass and identify all vertebrate classes.

METHODS AND RESULTS

The primers were designed by aligning and analyzing over 1500 16S rRNA sequences downloaded from the NCBI nucleotide database. A total of 93 vertebrate species, spanning 27 orders and 55 families, were PCR-amplified to validate the primers. All the target species were successfully amplified and identified when aligned with reference sequences from the NCBI nucleotide database. Using the Kimura 2-parameter model, low intra-species genetic divergence of the target region was observed - from 0 to 4.63%, whereas relatively higher inter-species genetic divergence was observed, ranging from 4.88% to 69.81%. Moreover, the newly developed primers were successfully applied to a direct PCR protocol, making the workflow very cost-effective, time-saving and less laborious in comparison to conventional PCR.

CONCLUSIONS

The short length, high variability and conserved priming sites of the target fragment across all vertebrate species make it a highly desirable marker for species identification and discrimination.

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.

Short targeting multiplex PCR assay to detect and discriminate beef, buffalo, chicken, duck, goat, sheep and pork DNA in food products

Food fraud is a global problem raising increased concerns during the past decades and food authenticity is now a burning issue. Beef, buffalo, chicken, duck, goat, sheep, and pork are heavily consumed meats bearing nutritional, economic and cultural/religious importance and are often found to be adulterated in raw and processed states. To authenticate these species, we developed and validated a highly specific multiplex (heptaplex) PCR assay targeting short length amplicons (73-263 bp) using seven pairs of species-specific primer sets targeting mitochondrial cytochrome b (cytb) and NADH dehydrogenase subunit 5 (ND5) genes. Specificity checking (in silico and in vitro) against 25 non-target species revealed no cross-species amplification. The developed multiplex assay was validated with various adulterated and heat-treated (boiled, microwaved and autoclaved) meatball products and were found to show high sensitivity and stability under all processing conditions. The assay was sensitive enough to detect 0.01-0.005 ng of DNA from raw meat and 0.5% (w/w) adulterated meat in mixed matrices. A market survey revealed mislabelling of 95% beef and 15% chicken products while pork products were found pure. Given some advantageous features including short sizes of amplicons, exceptional stability and superior sensitivity, the developed assay could be conveniently used for discriminatory detection of target species with a variety of raw meat as well as processed meat products undergoing extreme processing treatments.

A multidisciplinary approach for investigating dietary and medicinal habits of the Medieval population of Santa Severa (7th-15th centuries, Rome, Italy)

A multidisciplinary approach, combining stable isotope analysis from bone proteins and investigations on dental calculus using DNA analysis, light microscopy, and gas chromatography coupled with mass spectrometry, was applied to reconstruct dietary and medicinal habits of the individuals recovered in the cemetery of the Castle of Santa Severa (7^th-15^th centuries CE; Rome, Italy). Stable isotope analysis was performed on 120 humans, 41 faunal specimens and 8 charred seeds. Dental calculus analyses were carried out on 94 samples. Overall, isotope data indicated an omnivorous diet based on C₃-terrestrial protein, although some individuals possessed carbon values indicative of C₄ plant consumption. In terms of animal protein, the diet was probably based on cattle, sheep, pig and chicken products, as witnessed by the archaeozoological findings. Evidence from calculus suggested the consumption of C₃ cereals, Fabaceae, Fagaceae, milk and dairy products. Secondary metabolites of herbs and wine were also detected. The detection of marine fish ancient DNA, as well as of ω3 fatty acids in calculus, hypothesized the consumption of marine foodstuffs for this coastal population, despite the lack of a clear marine isotopic signal and the presence of polyunsaturated fatty acids in plant tissues. Moreover, the knowledge of ethnopharmacological tradition and the application of medicinal plants (e.g. Punica granatum L., Ephedra sp. L.) were also identified. The detection of artemisinin, known to have antimalarial properties, led to hypothesize the presence of malaria in the area. Altogether, the combined application of microscopy and biomolecular techniques provided an innovative reconstruction of Medieval lifeways in Central Italy.

Heptaplex Polymerase Chain Reaction Assay for the Simultaneous Detection of Beef, Buffalo, Chicken, Cat, Dog, Pork, and Fish in Raw and Heat-Treated Food Products

Species authentication of meat and fish products is crucial to safeguard public health, economic investment, and religious sanctity. We developed a heptaplex polymerase chain reaction assay targeting short amplicon length (73-198 bp) for the simultaneous detection and differentiation of cow, buffalo, chicken, cat, dog, pig, and fish species in raw and processed food using species-specific primers targeting mitochondrial cytb, ND5, and 16s rRNA genes. Assay validation of adulterated and various heat-treated meatball matrices showed excellent stability and sensitivity under all processing conditions. The detection limit was 0.01-0.001 ng of DNA under pure states and 0.5% meat in meatball products. Buffalo was detected in 86.7% (13 out of 15) of tested commercial beef products, while chicken, pork, and fish products were found to be pure. The developed assay was efficient enough to detect target species simultaneously, even in highly degraded and processed food products at reduced time.

Who were the miners of Allumiere? A multidisciplinary approach to reconstruct the osteobiography of an Italian worker community

This research presents an in-depth study of the skeletal remains collected from the archaeological site of Allumiere (15th-16th centuries CE; Rome, Italy). A multidisciplinary approach was used, combining skeletal biology, molecular anthropology and archaeobotany with the aim of reconstructing the osteobiography of the alum miners buried at the site. Since 1460, the area of the Tolfa Mountains was significant for the exploitation of alum which was used for a wide range of purposes in the Middle Ages, ranging from woven production to medical practice. A total of 70 individuals (63 adults and 7 juveniles) were studied. The sex ratio of the community indicated a higher prevalence of males with respect to females. Morphological examination indicated occupational musculoskeletal stress markers, which might reflect the specific phase of alum production that each individual was occupied in. Dietary reconstruction was primarily performed through carbon and nitrogen stable isotope analysis with integration of the results obtained by microscopic, genetic and GC-MS investigations on dental calculus. The diet was omnivorous, indicating a reliance on C3-terrestrial protein and evidence for limited C4 consumption by some individuals. Herbivores, such as sheep and cattle, appear to have contributed to the diet more than pigs and chickens. Consumption of Fagaceae and Poaceae species was predominant; moreover, indicators of Brassicaceae and milk and its derivatives were abundantly recurrent in the population, followed by plant oils and theophylline. Furthermore, the detection of pharmacological alkaloids indicated the knowledge and application of medicinal plants by the community. The novel use of multiple techniques based on cutting-edge technologies has provided a unique window on the lifestyles of individuals from one of the first Italian settlements of alum workers.

Qualitative and quantitative detection of chicken deoxyribonucleic acid (DNA) in dry dog foods

Chicken is a common protein source in pet foods and is concurrently listed among food allergens. Commercial over-the-counter (OTC) diets with an alternative animal protein source are considered suitable for dietary elimination trials by pet owners. The potential presence of undeclared chicken-derived ingredients in these diets can compromise the outcome of the trial during the diagnosis of adverse food reactions. The aim of this study was to selectively verify the absence or presence of chicken DNA in 10 OTC dry canine foods, using qualitative and quantitative approaches. The method of identification of chicken-derived protein was elaborated with the polymerase chain reaction (PCR) technology, whereas quantitative real-time PCR was used for the quantitative assessment. In most of the analysed samples, the chicken DNA was detectable; however, the quantified amounts were predominantly low, although differences between batches were observed.

Rapid bovine and caprine species identification in ruminant feeds by duplex real-time PCR melting curve analysis using EvaGreen fluorescence dye

A duplex real-time PCR assay with melting curve analysis, using the EvaGreen fluorescence dye, was developed for rapid and reliable identification of bovine and caprine in ruminant feeds. The method merges the use of bovine (Bos taurus) and caprine (Capra hircus) specific primers that amplify small fragments (bovine 96 bp and caprine 142 bp) of the mitochondrial 16S rRNA and 12S rRNA genes, respectively. DNA was isolated from heat-treated meats (133 °C/3 bar for 20 min) mixtures of bovine and caprine and was used to optimize the assay. Gene products of caprine and bovine produced two distinct melting peaks simultaneously at 82 and 86.8 °C, respectively. Duplex analysis of the reference samples showed that the detection limit of the assay was 0.003 % for bovine and 0.005 % for caprine species. The aim of this study was to develop a duplex real-time PCR assay followed by a melt curve step for sensitive, rapid, specific, and cost-effective detection of bovine and caprine species based on the amplicon melting peak in ruminant feeds to prevent Transmissible Spongiform Encephalopathies.