A basic amino acid found in many foods could be the key to making tuna significantly safer for consumption, according to research published in Global Challenges. Scientists have developed a packaging solution that can remove up to 35% of toxic mercury from canned tuna using cysteine, a naturally occurring compound.
The finding offers a potential solution to one of the most persistent problems in seafood safety: how to maintain the nutritional benefits of tuna while reducing exposure to mercury, a toxic heavy metal that accumulates in fish tissue.
“Our study shows that there are alternative approaches to addressing mercury contamination in tuna, rather than just limiting consumption,” said Mehdi Abdollahi, Associate Professor at Chalmers University of Technology and project coordinator. “Our goal is to improve food safety and contribute to enhanced human health, as well as to better utilise food that is currently under certain restrictions.”
The technique is remarkably straightforward: adding a 1.2% cysteine solution to the water-based liquid in which tuna is packed. The amino acid works by drawing mercury out of the fish tissue during storage, with no need for additional processing steps or changes to current manufacturing methods.
The World Health Organization lists mercury among the ten most harmful chemicals for humans, with particular concerns about its effects on developing fetuses and young children. This has led to restrictions on tuna consumption, especially for pregnant women.
What makes this approach particularly promising is its simplicity. Rather than requiring complex processing or additives, it uses a natural amino acid that’s already present in many foods. “The beauty of this type of packaging is that it is active while the product is on the shelf. No additional production steps would be needed if a method like this were used industrially,” explained Przemysław Strachowski, the study’s lead author.
The researchers found that the mercury reduction process reaches its maximum effectiveness within two weeks of packaging, with better results when there’s more surface area of fish in contact with the solution. The highest mercury reduction – 35% – was achieved with minced tuna, though significant reductions were also seen in whole pieces.
Importantly, cell-based safety tests showed no concerning effects from the treatment, and researchers reported no noticeable changes in the appearance or smell of the fish. The study evaluated various forms of tuna, from fresh fillets to commercial canned products, consistently demonstrating the technique’s effectiveness.
The research comes at a crucial time, as concerns about mercury contamination continue to limit the consumption of tuna, a protein-rich food that’s also an excellent source of omega-3 fatty acids and other nutrients. While current safety guidelines focus on restricting consumption, this development suggests a way to make tuna inherently safer.
The next challenge for researchers is developing methods to safely dispose of the mercury-containing solution. While the current study focused on proving the concept’s effectiveness, future work will need to address the full lifecycle of the extracted mercury to ensure environmental safety.
This development could represent a significant shift in how we approach food safety, moving from simply warning consumers about contamination risks to actively reducing those risks through smart packaging solutions.