Application of DNA barcoding for ensuring food safety and quality

Can consumers avoid mislabelling? Genetic species identification provides recommendations for shrimp/prawn products

BACKGROUND

Crustaceans of the superfamily Penaeoidea (e.g., shrimps and prawns) are among the most commercially available aquatic products worldwide. However, there are few studies regarding not only the presence but also the characteristics of mislabelling in these food products. Such information would be helpful for consumers in order to avoid the typical problems associated with mislabelling (e.g., health and economic issues). For this reason, this work considers Penaeoidea mislabelling by comparing different products (frozen, fresh, boiled), and sources (hypermarkets, supermarkets and fishmongers) from Spain (Europe).

RESULTS

A total of 94 samples from 55 different products were collected, representing 19 different species from 13 genera. Mitochondrial DNA (COI gene) was amplified, revealing mislabelling in almost 30% of supermarket products and almost exclusively found in frozen samples (95% of the total) regardless of its price. In addition, products from the Pacific Ocean seem to be particularly susceptible to mislabelling.

CONCLUSIONS

All in all, recommendations for the consumer in order to avoid mislabelling of prawns include purchasing them fresh from fishmongers; aquaculture products must not be avoided. This study represents, to our knowledge, the first attempt to provide recommendations to consumers based on DNA analyses in order to avoid mislabelling in food products. Further research is therefore required to provide such recommendations in different food products, particularly those that are processed, packaged and/or frozen. © 2024 The Author(s). Journal of the Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

How Helpful May Be a CRISPR/Cas-Based System for Food Traceability?

Genome editing (GE) technologies have the potential to completely transform breeding and biotechnology applied to crop species, contributing to the advancement of modern agriculture and influencing the market structure. To date, the GE-toolboxes include several distinct platforms able to induce site-specific and predetermined genomic modifications, introducing changes within the existing genetic blueprint of an organism. For these reasons, the GE-derived approaches are considered like new plant breeding methods, known also as New Breeding Techniques (NBTs). Particularly, the GE-based on CRISPR/Cas technology represents a considerable improvement forward biotech-related techniques, being highly sensitive, precise/accurate, and straightforward for targeted gene editing in a reliable and reproducible way, with numerous applications in food-related plants. Furthermore, numerous examples of CRISPR/Cas system exploitation for non-editing purposes, ranging from cell imaging to gene expression regulation and DNA assembly, are also increasing, together with recent engagements in target and multiple chemical detection. This manuscript aims, after providing a general overview, to focus attention on the main advances of CRISPR/Cas-based systems into new frontiers of non-editing, presenting and discussing the associated implications and their relative impacts on molecular traceability, an aspect closely related to food safety, which increasingly arouses general interest within public opinion and the scientific community.

Assessing arthropod biodiversity with DNA barcoding in Jinnah Garden, Lahore, Pakistan

Previous difficulties in arthropod taxonomy (such as limitations in conventional morphological approaches, the possibility of cryptic species and a shortage of knowledgeable taxonomists) has been overcome by the powerful tool of DNA barcoding. This study presents a thorough analysis of DNA barcoding in regards to Pakistani arthropods, which were collected from Lahore's Jinnah Garden. The 88 % (9,451) of the 10,792 specimens that were examined were able to generate DNA barcodes and 83% (8,974) of specimens were assigned 1,361 barcode index numbers (BINs). However, the success rate differed significantly between the orders of arthropods, from 77% for Thysanoptera to an astounding 93% for Diptera. Through morphological exams, DNA barcoding, and cross-referencing with the Barcode of Life Data system (BOLD), the Barcode Index Numbers (BINs) were assigned with a high degree of accuracy, both at the order (100%) and family (98%) levels. Though, identifications at the genus (37%) and species (15%) levels showed room for improvement. This underscores the ongoing need for enhancing and expanding the DNA barcode reference library. This study identified 324 genera and 191 species, underscoring the advantages of DNA barcoding over traditional morphological identification methods. Among the 17 arthropod orders identified, Coleoptera, Diptera, Hemiptera, Hymenoptera, and Lepidoptera from the class Insecta dominated, collectively constituting 94% of BINs. Expected malaise trap Arthropod fauna in Jinnah Garden could contain approximately 2,785 BINs according to Preston log-normal species distribution, yet the Chao-1 Index predicts 2,389.74 BINs. The Simpson Index of Diversity (1-D) is 0.989, signaling high species diversity, while the Shannon Index is 5.77, indicating significant species richness and evenness. These results demonstrated that in Pakistani arthropods, DNA barcoding and BOLD are an invaluable tool for improving taxonomic understanding and biodiversity assessment, opening the door for further eDNA and metabarcoding research.

Molecular Rapid Test for Identification of Tuna Species

Tuna is an excellent food product, relatively low in calories, that is recommended for a balanced diet. The continuously increasing demand, especially for bluefin-tuna-based food preparations, and its relatively high market price make adulteration by intentionally mixing with other lower-priced tunas more prospective. The development of rapid methods to detect tuna adulteration is a great challenge in food analytical science. We have thus developed a simple, fast, and low-cost molecular rapid test for the visual detection of tuna adulteration. It is the first sensor developed for tuna authenticity testing. The three species studied were Thunnus thynnus (BFT), Thunnus albacares, and Katsuwonus pelamis. DNA was isolated from fresh and heat-treated cooked fish samples followed by PCR. The PCR products were hybridized (10 min) to specific probes and applied to the rapid sensing device. The signal was observed visually in 10-15 min using gold nanoparticle reporters. The method was evaluated employing binary mixtures of PCR products from fresh tissues and mixtures of DNA isolates from heat-treated tissues (canned products) at adulteration percentages of 1-100%. The results showed that the method was reproducible and specific for each tuna species. As low as 1% of tuna adulteration was detected with the naked eye.

Fish DNA Sensors for Authenticity Assessment-Application to Sardine Species Identification

Food and fish adulteration is a major public concern worldwide. Apart from economic fraud, health issues are in the forefront mainly due to severe allergies. Sardines are one of the most vulnerable-to-adulteration fish species due to their high nutritional value. Adulteration comprises the substitution of one fish species with similar species of lower nutritional value and lower cost. The detection of adulteration, especially in processed fish products, is very challenging because the morphological characteristics of the tissues change, making identification by the naked eye very difficult. Therefore, new analytical methods and (bio)sensors that provide fast analysis with high specificity, especially between closely related fish species, are in high demand. DNA-based methods are considered as important analytical tools for food adulteration detection. In this context, we report the first DNA sensors for sardine species identification. The sensing principle involves species recognition, via short hybridization of PCR-amplified sequences with specific probes, capture in the test zone of the sensor, and detection by the naked eye using gold nanoparticles as reporters; thus, avoiding the need for expensive instruments. As low as 5% adulteration of Sardina pilchardus with Sardinella aurita was detected with high reproducibility in the processed mixtures simulating canned fish products.

Mitochondrial Analysis of Sparidae Species to Detect a New DNA Barcoding Marker for Dentex gibbosus to Utilize against Fraud

Dentex gibbosus (Pink dentex) is a fish species of increasing economic interest in the Mediterranean Sea that is consumed both whole and processed. The growing value of this sparid in European markets is responsible for its substitution with fraudulent species. The distinctive morphologic feature of D. gibbosus is the conspicuous hump on the forehead in the older and larger specimens. However, the head is regularly convex in young individuals, requiring high skills and competencies for correct identification. Authentication becomes even more challenging in the case of prepared and processed products. Therefore, the molecular characterization of Pink dentex plays a crucial role in preventing commercial fraud with species substitution. This paper proposes a comparative mitogenome analysis between 19 sparid species of commercial interest as a tool to accurately design species-specific primers targeting a fragment of the NAD2 gene for the identification of D. gibbosus. We successfully detected Pink dentex DNA both using endpoint and real-time PCR. The findings showed the high specificity of the designed primers, demonstrating this a suitable, fast, and cost-effective method that could be used for the unambiguous identification of Pink dentex. This innovative approach for sparid authentication is expected to contribute to seafood traceability, public health assurance, integrity, and the credibility of the seafood industry.