An investigation by NGOs (French) and (German) has analyzed 148 cans of tuna in five European countries and has found that 10% of them exceed the mercury levels allowed for fresh tuna, which in Spain are the same as for canned tuna (this is not the case in all countries). The Spanish Food Safety Agency (Aesan) points out that last year no non-compliance was detected in Spain for this reason, while the sector criticizes the report’s methodology and points out that in the last decade it has reviewed 8,000 samples and the vast majority meet the requirements. legal limits. Consumption—although the recommendation does not extend to cans made with other species of tuna—since .
The European Food Safety Authority imposes a limit of 0.5 milligrams per kilo (mg/kg) of mercury for seafood, which is reduced to 0.3 for small fish, such as cod, sardines and anchovies, and increases up to 1 mg/kg in the case of tuna. “There is no health reason for this discrepancy: mercury is no less toxic if it is ingested through tuna, which is also the most consumed fish in Europe,” says Julie Guterman, Bloom researcher and lead author of the study. “In many countries, the standard applies to fresh tuna and not canned tuna, which loses a lot of water, so the mercury can be two or three times more concentrated,” he adds. The Aesan – dependent on Consumer Affairs – confirms that this limit does apply in Spain to canned tuna.
The two entities have selected 148 cans from five countries (Spain, France, Italy, the United Kingdom and Germany) to analyze them. “Several supermarkets were chosen by lottery, and in each one ten cans were randomly chosen and sent to an independent laboratory, a specialist in mercury analysis,” says Guterman. The result —— is that, and even a can purchased in France almost quadruples it. Although not in all countries that means breaking the law. If the limit applied were the strictest (0.3 µg/kg), almost 60% of cans would be above it, according to the study.
Aesan points out that last year 319 mercury analyzes were carried out on fish and fishing products, of which 25 exceeded the legal limit (8%), although none of the non-compliance involved canned tuna. On the other hand, 4,021 inspections were carried out on manufacturers of fishing products and more than 9% did not comply with food regulations—not only in terms of contaminants. In 2013, the state agency conducted research and the average amount of mercury found was 0.26 mg/kg, within limits.
Roberto Alonso, general secretary of , which brings together 250 canning companies, responds that the current limit “is safe for health”: “What is really important is the Tolerable Weekly Intake (TWI), set at 1.3 milligrams per kilogram of weight. body weight per week, which ensures that the consumption of canned tuna in a varied and balanced diet is totally safe.” In addition, he points out that the entity’s laboratories have analyzed 8,000 samples in ten years. “Mercury levels in canned tuna are significantly below the legal limit, with a total mean of 0.29 mg/kg and a median of 0.19 mg/kg, given that the smallest specimens are usually used in canned tuna.” ”, he summarizes.
Regarding the report, he criticizes that it does not know if the correct methodology has been followed and the appropriate analyzes have been carried out so that the sample is representative: “Without this information, it is difficult to issue an assessment.” Furthermore, it ensures that if the industry finds that the limits are exceeded in any case, the batch is rejected. “Canning companies implement rigorous self-control plans for their products and monitor the sizes of raw materials with the aim of guaranteeing 100% compliance,” he says.
Some criticism shared by Javier Garat, general secretary of , which represents the shipowners: “The report is very biased and does not adjust to reality. Entities like Aesan guarantee that legal levels are met.” Garat points out that if a batch is found that exceeds the figures, it is withdrawn. In addition, he points out that tuna “have a high selenium content, which acts like a magnet with mercury, producing a mercury-selenium substance that the body easily eliminates.” The two NGOs, however, defend the validity of the analysis.
Environmental pollutants
The European Commission guarantees food safety based on the opinions of the EFSA, which bases its reports and opinions on scientific data. In relation to environmental contaminants, such as mercury, it has followed the criterion that its presence is “as low as reasonably possible” (Alara, for its acronym in English). It is about finding a balance between minimizing health risks and the ability of an industry to comply with established limits so that production is not affected.
“Some contaminants, such as mercury, accumulate naturally in certain species due to their place in the food chain. For example, large fish like tuna have more mercury because they are at the top of the food chain and live longer, which increases their exposure. This justifies a higher limit for tuna than for smaller fish,” explains , a food safety expert.
“If too strict a limit were set, tuna could disappear from supply, as it would be difficult to find products that meet such low contaminant levels,” he continues. “In addition, the general pattern of consumption of that food within the population must be taken into account: those foods that are consumed more frequently will have stricter limits.”
Neither EFSA nor the EC have reacted to the report. The European Commission explains that the maximum levels of contaminants in food are established in accordance with the EFSA’s prior assessment of whether it poses a health risk. In the case of mercury, EFSA checks whether the exposure of European consumers to the pollutant exceeds the tolerable weekly intake (TWI).
If we take as a reference the 0.26 mg/kg found on average by Aesan in Spanish cans, and taking into account that an average can has 60 grams of drained weight (tuna), the average amount per can would be about 15.6 milligrams of mercury per can. If we divide 80 kilos of weight by those 15.6 milligrams, the consumption of about six typical cans of tuna per week would still be safe. On the other hand, Bloom and Foodwatch carry out other calculations (estimating 90% methylmercury contamination in those 100 grams) and believe that three and a half cans should not be exceeded. They also ask the authorities to reduce these limits.
because mercury can be a neurological toxicant in the early stages of development and generate cognitive declines, neuromotor and attention disorders. Garat, from Cepesca, points out that the warning refers only to bluefin tuna, while cans are usually made with other tuna (such as skipjack, yellowfin or bigeye), which have a lower content of heavy metals. The agency launched this warning in 2019 following the results of several biomonitoring studies that confirmed that modifying the diet in favor of species with low mercury content (such as anchovies, squid, octopus, salmon, squid or trout), reduces the presence of mercury in hair and exposure to this contaminant.
The Ministry of Health plans to start the first major state study in December to see how the chemical substances to which we are exposed on a daily basis affect us, one of which is mercury. , the initiative is part of the new national human biomonitoring structure and aims to measure the levels of contaminants in thousands of volunteers as a first step to then take public health measures based on science.
