Authentication of traditional meat products (Haleem) sold in India: a first report confirming species mislabelling

Traditional meat products like Haleem play a pivotal role in the culinary landscapes of Indian consumers, along with high economic value and business potential. Due to anticipated gains associated with adulterating 'Haleem' and constant evasion from regulatory oversight, the susceptibility to adulteration has substantially increased. Furthermore, no reports/surveillance regarding their labelling compliance has been reported. Hence, we conducted a 2-year surveillance using 100 samples collected from Hyderabad, India, using the Chipron™ DNA macroarray analysis technique. The method was validated for sensitivity (1%), specificity, and with proficiency test samples. Following this, the surveillance samples (beef, chicken, and mutton Haleem) were tested. The surveillance revealed an alarming adulteration of 46% of the samples, with different proportions of adulterant species. Adulteration of unconventional meat like camel meat was also found. These concerning results necessitate the requirement of stricter and constant regulatory surveillance to safeguard consumer trust and preserve the authenticity of traditional meat products.

Supplementary Information

The online version contains supplementary material available at 10.1007/s13197-024-05947-9.

DNA barcoding continues to identify endangered species of shark sold as food in a globally significant shark fin trade hub

Shark fins are a delicacy consumed throughout Southeast Asia. The life history characteristics of sharks and the challenges associated with regulating fisheries and the fin trade make sharks particularly susceptible to overfishing. Here, we used DNA barcoding techniques to investigate the composition of the shark fin trade in Singapore, a globally significant trade hub. We collected 505 shark fin samples from 25 different local seafood and Traditional Chinese Medicine shops. From this, we identified 27 species of shark, three species are listed as Critically Endangered, four as Endangered and ten as Vulnerable by the International Union for Conservation of Nature (IUCN). Six species are listed on CITES Appendix II, meaning that trade must be controlled in order to avoid utilization incompatible with their survival. All dried fins collected in this study were sold under the generic term "shark fin"; this vague labelling prevents accurate monitoring of the species involved in the trade, the effective implementation of policy and conservation strategy, and could unwittingly expose consumers to unsafe concentrations of toxic metals. The top five most frequently encountered species in this study are Rhizoprionodon acutus, Carcharhinus falciformis, Galeorhinus galeus, Sphyrna lewini and Sphyrna zygaena. Accurate labelling that indicates the species of shark that a fin came from, along with details of where it was caught, allows consumers to make an informed choice on the products they are consuming. Doing this could facilitate the avoidance of species that are endangered, and similarly the consumer can choose not to purchase species that are documented to contain elevated concentrations of toxic metals.

Endangered shark species traded as "cação" in São Paulo during the COVID-19 lockdown: DNA-barcoding a snapshot of products

BACKGROUND

Elasmobranch populations are declining, predominantly driven by overfishing, and over a third of global sharks, rays, and chimeras are estimated to be threatened with extinction. In terms of trade, Brazil is ranked the eleventh-largest shark producer and the top importer of shark meat in the world. Research has shown that elasmobranchs are sold in Brazil under the name "cação" (a generic designation for cartilaginous fish) to overcome consumer resistance.

METHODOLOGY AND RESULTS

This study used DNA barcoding to investigate the sale of sharks in the State of São Paulo during the COVID-19 lockdown. A total of 35 samples of "cação" were analysed, revealing six different shark species on sale, including Carcharhinus falciformis, Carcharhinus signatus, Carcharias taurus, Isurus oxyrinchus, and Isurus paucus, that are threatened with extinction according to the IUCN red list. This study demonstrates that vulnerable elasmobranchs are being commercialised under the label "cação" in the São Paulo State and Brazil.

CONCLUSIONS

Comparison of shark products traded before and during the COVID-19 pandemic showed no significant difference, suggesting lockdown did not affect patterns of species commercialisation. Effective fisheries and sale monitoring, correct product labelling legislation and increased consumer awareness that "cação" is shark are needed for appropriate conservation and management of shark populations in Brazil.

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.

Non-destructive Near Infrared Spectroscopy for the labelling of frozen Iberian pork loins

Iberian pigs fed on acorns and pasture were slaughtered from January until March of 2018 and 2019. The meat from those Iberian pigs is a seasonal food that only can be found fresh, at the marketplace, during a limit period of the year. Selling frozen-thawed meat is a legal practice, but consumers must be informed about it on the product label. However, to declare as fresh meat, meat previously frozen, is one of the most frequent meat frauds. The present study compares the performance of two rather different Near Infrared Spectroscopy instruments, based on Fourier Transform and Linear Variable Filter technologies, for the in-situ detection of fresh and frozen-thawed acorns-fed Iberian pig loins using Partial Least Discriminant Analysis (PLS-DA). The performance of the models developed for both instruments offered a very high discriminant ability. Furthermore, the models showed consistent results and interpretation when were evaluated with several scalars and graphical methods.

Detecting mislabelling in meat products using PCR-FINS

Economically motivated adulteration (EMA) or misrepresentation of meat products is of concern, especially in developing countries, due to obvious health hazards and religious sensitivities. As Indian cooking involves prolonged heat treatments and addition of spices and condiments, species authentication of food, especially meat products, may be challenging. This study evaluated the efficacy of Polymerase Chain Reaction-Forensically Informative Sequencing (PCR-FINS) in meat speciation of highly processed meat. Further the prevalence of mislabelling in processed and deeply cooked meat products being sold in supermarkets and restaurants in a south Indian city was investigated. FINS targeting the mitochondrial cytochrome b gene and the ATP synthase gene was applied to identify meat species of 106 meat products labelled as chicken, beef, carabeef, mutton and pork. Mislabelling was detected in more than half of mutton (52.3%) and carabeef (55.5%), and in under a third (27.2%) of beef products. PCR-FINS is a reliable method for meat species identification even in highly processed food but there is a need for appropriate universal primers which can target all common species used in meat products. This study is the first of its kind from the South Indian state of Kerala.

Re-visiting the occurrence of undeclared species in sausage products sold in Canada

Meat and poultry are major protein sources for humans worldwide. Undeclared ingredients in processed meat products, like sausage, continue to be identified in retail products all over the world. In collaboration with the Canadian Food Inspection Agency, a previous study of products purchased in Canada showed 20% mislabelling rate in sausage meats when tested for beef, pork, chicken, turkey and horse using DNA barcoding and digital PCR. In a follow-up to this study, an additional 100 "single species" sausage products were collected from Canadian retail markets, one year after our earlier study, to determine the prevalence of undeclared meat species in sausage. A new hierarchy of complementary molecular methods was applied in this study, including the testing of new target species (sheep and goat), in addition to beef, pork, chicken, turkey and horse. First, all samples were tested using DNA barcoding using universal primers, which revealed that 97% of the samples contained the declared species, presumably as the predominant species. Second, all samples were tested using ddPCR assays specifically targeting beef, pork, chicken, and turkey, which revealed that five beef samples, three chicken samples and two turkey samples contained undeclared species. Additionally, ddPCR revealed the presence of undeclared sheep in five samples. Overall, using complementary molecular methods, 14% of the samples contained additional undeclared species. It was encouraging to find a reduced rate of mislabelling compared to the previous study, though it remains clear that meat mislabelling is still an issue affecting Canadian consumers. The results from this study can be used to support decision-making processes for future inspection and monitoring activities in order to control species substitution or adulteration to protect consumers.

Harnessing mtDNA variation to resolve ambiguity in 'Redfish' sold in Europe

Morphology-based identification of North Atlantic Sebastes has long been controversial and misidentification may produce misleading data, with cascading consequences that negatively affect fisheries management and seafood labelling. North Atlantic Sebastes comprises of four species, commonly known as ‘redfish’, but little is known about the number, identity and labelling accuracy of redfish species sold across Europe. We used a molecular approach to identify redfish species from ‘blind’ specimens to evaluate the performance of the Barcode of Life (BOLD) and Genbank databases, as well as carrying out a market product accuracy survey from retailers across Europe. The conventional BOLD approach proved ambiguous, and phylogenetic analysis based on mtDNA control region sequences provided a higher resolution for species identification. By sampling market products from four countries, we found the presence of two species of redfish (S. norvegicus and S. mentella) and one unidentified Pacific rockfish marketed in Europe. Furthermore, public databases revealed the existence of inaccurate reference sequences, likely stemming from species misidentification from previous studies, which currently hinders the efficacy of DNA methods for the identification of Sebastes market samples.

Case-control studies in diabetes. Do they really use a case-control design?

AIMS

Studies defined as case-control do not always use this design. We aimed to estimate the frequency of mislabelled case-control studies in published articles in the area of diabetes and to identify the predictors of incorrect labelling.

METHODS

We searched Medline and Web of Science for articles with "diabetes" and "case control" in title and filtered for language (English/Romance) and period (January 2010-December 2014). Inclusion criteria were: (1) statement to use a case-control design in title, (2) to be a final full-length publication and (3) to have original data in the area of diabetes. Three independent reviewers went through titles, looked for full texts and reviewed them. Discrepancies were settled with a fourth reviewer. Expert epidemiologist advice was requested in case of doubt.

OUTCOME VARIABLE

case-control mislabelling; addressed predictors: publication year, journal impact factor and journal subject.

STATISTICS

proportion of mislabelled CC articles and assessment of predictors by multivariate logistic regression analysis.

RESULTS

We retrieved 362 articles, 251 of them fulfilling inclusion criteria. The proportion of mislabelled CC studies was 43.8% (confidence interval 95% 37.7-50.0%). Most mislabelled studies had a cross-sectional design (82.7%). Predictors of mislabelling were publication year, journal impact factor and journal area.

CONCLUSIONS

A relevant subset of studies defined as case-control in the area of diabetes correspond to mislabelled cross-sectional studies. Incorrect labelling misleads readers regarding the interpretation of results and the cause-effect hypothesis. Researchers, reviewers and editors should be aware of and commit to settle this issue.

Sushi barcoding in the UK: another kettle of fish

Although the spread of sushi restaurants in the European Union and United States is a relatively new phenomenon, they have rapidly become among the most popular food services globally. Recent studies indicate that they can be associated with very high levels (>70%) of fish species substitution. Based on indications that the European seafood retail sector may currently be under better control than its North American counterpart, here we investigated levels of seafood labelling accuracy in sushi bars and restaurants across England. We used the COI barcoding gene to screen samples of tuna, eel, and a variety of other products characterised by less visually distinctive ‘white flesh’. Moderate levels of substitution were found (10%), significantly lower than observed in North America, which lends support to the argument that public awareness, policy and governance of seafood labels is more effective in the European Union. Nevertheless, the results highlight that current labelling practice in UK restaurants lags behind the level of detail implemented in the retail sector, which hinders consumer choice, with potentially damaging economic, health and environmental consequences. Specifically, critically endangered species of tuna and eel continue to be sold without adequate information to consumers.

Mislabelling and Species Substitution in Fishery Products Retailed in Sardinia (Italy), 2009-2014

Mislabelling and species substitution are major concerns for fishery products marketed in the EU. The present survey aimed to investigate the correct enforcement of the Community and National rules on the labelling and marketing of fishery products retailed in Sardinia (Italy) between 2009 and 2014. A total of 3000 labels for fresh unpacked fishery products have been considered. A total of 900 labels (30%) presented non-compliance concerning the wrong trade name, the wrong or missing information about the catch area and the production method. The highest percentage of mislabelling and species substitution has been detected in open-air markets (65%) and small-scale retail shops (40%) compared with the big supermarket chains (10%). The high percentage of non-compliances with the European and Italian legislation highlights the need to improve the essential information demanded by consumers on fishery products marketed in open-air markets and small-scale retail shops. While there are laws in place, it is unclear how effective they are and what type of penalties food business operators of open-air markets and small-scale retail shops may incur.

Occurrence of Mislabelling in Prepared Fishery Products in Southern Italy

Fish authentication is a major concern not only for the prevention of commercial fraud, but also for the assessment of safety risks deriving from the undeclared introduction of potentially dangerous toxic or allergenic substances or environmentally damaging fish where endangered species are involved. Moreover, food authentication might affect the diet of certain groups of consumers, such as followers of religious practices. Considering the authentication of fish products is one of the key issues in food safety, quality and sustainability, the aim of this work was to investigate the prevalence of mislabelling in sole (Solea solea), plaice (Pleuronectes platessa), Atlantic salmon (Salmo salar), and hake (Merluccius merluccius) fillets from markets and supermarkets located in Apulia (Southern Italy) using DNA barcoding. The results of the molecular investigations reveal that 42/98 (42.8%) fillet samples were not correctly labelled. In particular, 12/27 (44.4%) fillets of sole (Solea solea) were identified as belonging to Solea senegalensis. In addition, 13/28 (46.4%) plaice (Pleuronectes platessa) samples were identified as Pangasius hypophtalmus. All Atlantic salmon (Salmo salar) samples were correctly labelled. Post-sequencing data analysis revealed that 17/30 (56.6%) hake fillets (Merluccius merluccius) were not correctly labelled, of which 8/30 samples identified as Merluccius hubbsi, 5/30 samples as Merluccius products and 4/30 as Merluccius capensis. The study reveals a high occurrence of species mislabelling in the prepared fish fillet products, further evidence of the need for increased traceability and assessment of the authenticity of food products.

Fish species substitution and misnaming in South Africa: An economic, safety and sustainability conundrum revisited

While fish species mislabelling has emerged as a global problem, the tracking of improvements or deteriorations in seafood trading practices is challenging without a consistent basis for monitoring. The aim of this study was to develop a robust, repeatable species authentication protocol that could be used to benchmark the current and future incidences of fish mislabelling in South Africa. Using this approach, 149 fish samples collected from restaurants and retailers in three provinces (KwaZulu-Natal, Western Cape and Gauteng) were identified using DNA barcoding, supplemented in certain cases with mitochondrial control region sequencing. Overall, 18% of samples were incorrectly described in terms of species, with similar misrepresentation rates in restaurants (18%) and retail outlets (19%). While there appears to be some improvement in the transparency of local seafood marketing compared to previous studies, the results remain of concern and signal the need for enhanced seafood labelling regulations, monitoring and law enforcement.

Fish mislabelling in France: substitution rates and retail types

Market policies have profound implications for consumers as well as for the management of resources. One of the major concerns in fish trading is species mislabelling: the commercial name used does not correspond to the product, most often because the product is in fact a cheaper or a more easily available species. Substitution rates depend heavily on species, some often being sold mislabelled while others rarely or never mislabelled. Rates also vary largely depending on countries. In this study, we analyse the first market-wide dataset collected for France, the largest sea food market in Europe, for fish species substitution. We sequenced and analysed 371 samples bearing 55 commercial species names, collected in fishmonger shops, supermarkets and restaurants; the largest dataset assembled to date in an European country. Sampling included fish fillets, both fresh and frozen, and prepared meals. We found a total of 14 cases of mislabelling in five species: bluefin tuna, cod, yellowfin tuna, sole and seabream, setting the overall substitution rate at 3.7% CI [2.2-6.4], one of the lowest observed for comparable surveys with large sampling. We detected no case of species mislabelling among the frozen fillets or in industrially prepared meals, and all the substitutions were observed in products sold in fishmongers shops or restaurants. The rate of mislabelling does not differ between species, except for bluefin tuna. Despite a very small sample size (n = 6), the rate observed for this species (83.3% CI [36-99]) stands in sharp contrast with the low substitution rate observed for the other substituted species. In agreement with studies from other countries, this work shows that fish mislabelling can vary greatly within a country depending on the species. It further suggests that more efforts should be directed to the control of high value species like bluefin tuna.

Climatic and geographical dependence of the H, C and O stable isotope ratios of Italian wine

In this study, we investigated the relationship between (D/H)1, (D/H)2 and δ(13)C of ethanol and δ(18)O of water in wine, and variables describing the climate and the geography of the production area, using exploratory visualisation tools, regression analysis and linear modelling. For the first time, a large amount of data (around 4000 wine samples collected over 11 years in Italy) and all the official isotopic parameters, as well as a large number of significant climatic and geographical descriptors (date of harvest, latitude, longitude, elevation, distance from the sea, amount of precipitation, maximum daily temperature, minimum daily temperature, mean daily temperature, δ(18)O and δ(2)H of precipitation) were considered. δ(18)O, followed by (D/H)1, was shown to have the strongest relationship with climate and location. The dominant variables were latitude, with a negative relationship, δ(18)O and δ(2)H of precipitation and temperature, both with positive relationships. The identified correlations and models could be used to predict the isotopic composition of authentic wines, offering increased possibilities for detecting fraud and mislabelling.

DNA barcoding unveils skate (Chondrichthyes: Rajidae) species diversity in 'ray' products sold across Ireland and the UK

Skates are widely consumed across the globe, but many large species are subject to considerable concern regarding their conservation and management. Within Europe such issues have recently driven policy changes so that, for the first time, reports of skate landings now have to be made under species-specific names. Total allowable catches have also been established for many groups, which have been set to zero for a number of the most vulnerable species (e.g., Dipturus batis, Raja undulata and Rostoraja alba). Whilst accurate species identification has become an important issue for landings, the sale of skates is still usually made under a blanket term of “skate” or “ray”. The matter of identifying species of skate is further complicated by their morphologically conservative nature and the fact that they are commercially valued for their wings. Thus, before sale their bodies are usually discarded (i.e., “winged”) and often skinned, making morphological identification impossible. For the first time, DNA barcoding (of the mitochondrial COI gene) was applied to samples of skate wings from retail outlets across the British Isles, providing insight into which species are sold for consumption. A total of 98 wing samples were analysed, revealing that six species were sold; blonde ray (Raja brachyura), spotted ray (Raja montagui), thornback ray (Raja clavata), cuckoo ray (Leucoraja naevus) small-eyed ray (Raja microocellata) and shagreen ray (Leucoraja fullonica). Statistical testing demonstrated that there were significant differences in the species sold in the distinct retail groups which suggests complex drivers behind the patterns of sale in skates. The results also indicate that endangered species are not commonly being passed on to consumers. In addition, the practice of selling skate wings under ambiguous labels is highlighted as it makes it extremely difficult for consumers to exercise a right to avoid species of conservation concern. Interestingly, a single retailer chain labelled their wings as originating from three smaller-growing species (generally to be considered of lower conservation concern); of the six samples analysed from this company a third were mislabelled and originated from the thornback ray (a larger species that is currently undergoing population declines).