Application of DNA mini-barcoding and infrared spectroscopy for the authentication of the Italian product “bottarga”

DNA mini-barcoding reveals the mislabeling rate of canned cat food in Taiwan

Background

Domestic cats are important companion animals in modern society that live closely with their owners. Mislabeling of pet food can not only harm pets but also cause issues in areas such as religious beliefs and natural resource management. Currently, the cat food market is booming. However, despite the risk that mislabeling poses to cats and humans, few studies have focused on species misrepresentation in cat food products.

Methods

To address this issue, we used DNA barcoding, a highly effective identification methodology that can be applied to even highly processed products. We targeted a short segment (~85 basepairs) of the mitochondrial 16S rRNA (16S) gene as a barcode and employed Sanger or next generation sequencing (NGS) to inspect 138 canned cat food products in the Taiwanese market.

Results

We discovered that the majority of mislabeling incidents were related to replacement of tuna with other species. Moreover, our metabarcoding revealed that numerous undeclared ingredients were present in all examined canned products. One product contained CITES Appendix II-listed shortfin mako shark (Isurus oxyrinchus). Overall, we uncovered a mislabeling rate of at least 28.99%. To verify cases of mislabeling, an official standardized list of vernacular names, along with the corresponding scientific species names, as well as a dependable barcoding reference sequence database are necessary.

Check Your Shopping Cart: DNA Barcoding and Mini-Barcoding for Food Authentication

The molecular approach of DNA barcoding for the characterization and traceability of food products has come into common use in many European countries. However, it is important to address and solve technical and scientific issues such as the efficiency of the barcode sequences and DNA extraction methods to be able to analyze all the products that the food sector offers. The goal of this study is to collect the most defrauded and common food products and identify better workflows for species identification. A total of 212 specimens were collected in collaboration with 38 companies belonging to 5 different fields: seafood, botanicals, agrifood, spices, and probiotics. For all the typologies of specimens, the most suitable workflow was defined, and three species-specific primer pairs for fish were also designed. Results showed that 21.2% of the analyzed products were defrauded. A total of 88.2% of specimens were correctly identified by DNA barcoding analysis. Botanicals (28.8%) have the highest number of non-conformances, followed by spices (28.5%), agrifood (23.5%), seafood (11.4%), and probiotics (7.7%). DNA barcoding and mini-barcoding are confirmed as fast and reliable methods for ensuring quality and safety in the food field.

Pragmatic applications of DNA barcoding markers in identification of fish species – a review

DNA barcoding and mini barcoding involve Cytochrome Oxidase Subunit I (COI) gene in mitochondrial genome and is used for accurate identification of species and biodiversity. The basic goal of the current study is to develop a complete reference database of fishes. It also evaluates the applicability of COI gene to identify fish at the species level with other aspects i.e., as Kimura 2 parameter (K2P) distance. The mean observed length of the sequence was ranging between 500 to 700 base pairs for fish species in DNA barcoding and 80 to 650 base pairs for DNA mini barcoding. This method describes the status of known to unknown samples but it also facilitates the detection of previously un-sampled species at distinct level. So, mini-barcoding is a method focuses on the analysis of short-length DNA markers has been demonstrated to be effective for species identification of processed food containing degraded DNA. While DNA meta-barcoding refers to the automated identification of multiple species from a single bulk sample. The may contain entire organisms or a single environmental sample containing degraded DNA. Despite DNA barcoding, mini barcoding and meta-barcoding are efficient methods for species identification which are helpful in conservation and proper management of biodiversity. It aids researchers to take an account of genetic as well as evolutionary relationships by collecting their morphological, distributional and molecular data. Overall, this paper discusses DNA barcoding technology and how it has been used to various fish species, as well as its universality, adaptability, and novel approach to DNA-based species identification.

A Fast and Simple DNA Mini-barcoding and RPA Assay Coupled with Lateral Flow Assay for Fresh and Canned Mackerel Authentication

Nowadays, food authentication is more and more required given its relevance in terms of quality and safety. The seafood market is heavily affected by mislabelling and fraudulent substitutions/adulterations, especially for processed food products such as canned food items, due to the loss of morphological features. This study aims to develop new assays based on DNA to identify fresh mackerel (Scomber spp.) and commercial products. A new primer pair was de novo designed on the 5S rRNA gene and non-transcribed spacer (NTS), identifying a DNA mini-barcoding region suitable for species identification of processed commercial products. Moreover, to offer a fast and low-cost analysis, a new assay based on recombinase polymerase amplification (RPA) was developed for the identification of fresh 'Sgombro' (Scomber scombrus) and 'Lanzardo o Occhione' (Scomber japonicus and Scomber colias), coupled with the lateral flow visualisation for the most expensive species (Scomber scombrus) identification. This innovative portable assay has great potential for supply chain traceability in the seafood market.

Graphical Abstract

Supplementary Information

The online version contains supplementary material available at 10.1007/s12161-022-02429-6.

DNA Barcode Identification of Fish Products from Guiyang Markets in Southwestern People's Republic of China

ABSTRACT

Global fish consumption is increasing in tandem with population growth, resulting in the dilemma of overfishing. Overfished high-value fish are often replaced with other fish in markets. Therefore, the accurate identification of fish products in the market is important. In this study, full-DNA and mini-DNA barcoding were used to detect fish product fraud in Guiyang, Guizhou Province, People's Republic of China. The molecular results revealed that 39 (20.42%) of the 191 samples were inconsistent with the labels. The percentages of mislabeling of fresh, frozen, cooked, and canned fish products were 11.70, 20.00, 34.09, and 50.00%, respectively. The average Kimura two-parameter distances of mini-DNA barcoding within species and within genera were 0.56 and 6.42%, respectively, and those of full-DNA barcoding were 0.53 and 7.25%, respectively. Commercial fraud was evident in this study; most high-priced fish were replaced with low-priced fish with similar features. Our findings indicate that DNA barcoding is an effective tool for identifying fish products and could be used to enhance transparency and fair trade in domestic fisheries.

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