About 30% of seafood products like cod or salmon across the world may be mislabelled, according to a recent review. The analysis showed that on average nearly a third of all fish products that were tested didnt match the species stated on the label or food menu.
Seafood fraud undermines consumer trust and threatens the reputation of seafood businesses and the sustainability of global fishery resources.
It might be easy enough to tell your duck from chicken but when it comes to seafood its a lot more challenging. From haddock to herring, abalone to clams, theres a huge variety of seafood that can come in many forms. And, as one of the most traded food commodities in the world, seafood supply chains are complex.
Together these factors produce an intrinsic vulnerability to the potential of food fraud.
The motive for mislabelling is usually financial: companies that seek to make more profit by passing off a lower value species for more expensive ones. For instance a restaurant in Brussels was found to be selling cheaply farmed catfish as more expensive wild-caught cod.
But it also happens because of misidentification. This can happen for a number of reasons: a closely related species mixed at point of capture, confusion over common names of species along the supply chain, regional variation of names or the use of catch-all names like snapper or skate.
This is a problem. Firstly, the seafood could have been caught illegally. Secondly, it could hide the fact that endangered species are being sold to unsuspecting consumers. An incident in the UK earlier this year brought the problem to light DNA tests showed that fish and chip shops were selling endangered sharks.
One way to prevent seafood fraud and mislabelling is to use systems that certify where the product comes from.
In our new paper we used DNA testing to verify if such certification schemes work. The one we tested was the Marine Stewardship Council certification program which includes a system that requires a products origin to be traceable.
Our research is the largest and most comprehensive global assessment of species validation of Marine Stewardship Council labelled products. We found that only 13 of the 1402 certified seafood products were incorrectly labelled, representing less than 1%.
Compared with an average mislabelling rate of 30%, our results suggest that combining regular DNA testing with documentary trace-backs across the full supply chain can effectively prevent systematic and deliberate species substitution and fraud.
What we found
The Marine Stewardship Council is one of the most widely recognised certification and eco-labelling schemes aimed towards creating sustainable fisheries.
It is one of a few that includes a chain of custody traceability system, designed to prevent product substitution and fraud. This requires that every operator in the seafood supply chain implement a system that ensures certified products can be traced and correctly identified at every step. The system is regularly verified by independent auditors.
Working with two independent laboratories TRACE Wildlife Forensics Network and Science and Advice for Scottish Agriculture we tested the system which is currently used by over 4000 businesses at more than 44 000 locations in 100 countries.
We used DNA barcoding to validate the species identity of 1402 certified seafood products derived from 27 species across 18 countries.
To identify the species in a product, a DNA sample is taken and queried against a global database the Barcode of Life Data System which contains sequences from hundreds of thousands of species. This has been a successful forensic tool in identifying mislabelled seafood, including some firm favourites like sushi.
The results showed only 13 were incorrectly labelled, representing less than 1%. For these mislabelled products, records were obtained from each company at each step in the supply chain. Trace-backs revealed that only two of the samples could be confirmed as intentional substitutions with species of non-certified origin. The companies implicated had their chain of custody certificates suspended.
Although the system works, its impact as a global solution to fraud is limited because the system is voluntary. Companies have to choose whether they want to follow the processes and be certified. And so it ultimately depends on consumers choosing products because they are certified and creating that market incentive.
The good news is that consumers are starting to demand certification. In a global survey of 25 000 consumers in 22 countries, over 70% demanded independent verification of sustainability claims in supermarkets. This is a strong incentive for companies to use traceability systems and have certified products in store, on fresh fish counters and on restaurant menus.
With the right systems in place, seafood fraud is preventable. Consumers can create a change by demanding sustainable and traceable seafood, and by holding dealers accountable for their products.