By Marine Friant-Perrot, Lecturer at the Faculty of Law of Nantes
What are the regulations on the mercury content of tuna?
Mercury poses a major health risk. Considered by the World Health Organization (WHO) as one of the ten chemical substances of greatest concern for global public health, this neurotoxicant presents serious risks for the human body and more particularly for the brain development of fetuses and young children. As a result of chemical pollution of water due to coal combustion, mining and certain industrial activities such as cement manufacturing, this heavy metal is found in tuna, which is one of the main contributors to exposure. food with mercury.
To prevent this known risk, the presence of this contaminant in fish is regulated at European level by Commission Regulation (EU) 2023/915 of April 25, 2023 which sets maximum levels for certain contaminants in foodstuffs. The established value is 1.0 mg/kg for the different species of fresh tuna. Despite this text, the report published by Bloom reveals that, out of 148 cans of tuna tested, “more than one can in two tested exceeds the most restrictive maximum mercury content defined for seafood products (0.3 mg/kg)”, and “more than one can in ten exceeds the level defined for fresh tuna”.
What are the inconsistencies and gray areas of this regulation?
What the study points out are the inconsistencies in the regulations which apply different contamination thresholds for the same category of foods: those from fishing products and molluscs. The strictest maximum mercury limit set for fish is 0.3 mg/kg, but it does not apply to all seafood products. Higher levels may apply: 0.5 mg for shellfish, mollusk, and 1mg/kg for certain species of fish such as tuna or swordfish. The mercury concentration in tuna can therefore be three times higher than in mackerel or sardines, even though the health risk is identical. Another inconsistency existing before 2017 can be noted. Until the adoption of Regulation (EU) 2017/2229, the maximum mercury levels for co-products and by-products intended for pet food were lower than those applicable to tuna intended for human consumption. This threshold was raised citing the shortage caused by this more demanding maximum limit. Thus tuna cat or dog food may in the past have been less contaminated with mercury than the tuna we consume!
In addition to these inconsistencies, gray areas are also revealed. Regulations set maximum mercury levels for fresh tuna. What about the applicable thresholds for canned tuna that is cooked and dehydrated? For canned tuna (as well as for any dried, diluted, processed and/or compound foodstuff), in accordance with Article 3 of Regulation (EU) 2023/915, processing factors must be applied in order to be able to compare these values with the maximum content which applies to the product if it had been taken fresh. However, the professionals who process these foods are the only ones able to indicate these specific factors, linked to the recipe used. If overall, the tuna canning process leads to an increase in the mercury concentration linked to the dehydration of the product, this increase varies depending on the products and brands, these differences being due to cooking or the addition of ingredients like salt or lemon. In principle, operators should therefore provide public authorities with specific processing factors to enable control of finished products, but in practice, this data is not transmitted. This thesis is corroborated by a technical instruction from the DGAL of January 10, 2022 relating to the Monitoring Plan for chemical contaminants in the aquatic environment in fishery products which specifies that it is preferable for the operator to carry out self-checks on the flesh of fish rather than canned foods. Thus, on the side of operators subject to an obligation of self-control, as on the side of the DGAL during official controls, compliance with the maximum contaminant limits is not guaranteed for canned tuna, since the passage from fresh to canned constitutes a black box in terms of its effect on mercury concentration.
Same health risks and different rules: what are the prospects for lowering mercury contamination thresholds?
The variability of risk management measures depending on the fish species and the processing process constitutes an inconsistency that should be remedied. What are the obstacles to aligning the maximum mercury limits for tuna with other fish such as pollack, cod or mackerel? Tuna is the most consumed fish in Europe and if we strengthen the health standards applicable to mercury pollution, the resource will be impacted. This implies a transition towards food consumption patterns that are more respectful of health and the environment, in accordance with the ambition displayed by the European Commission in its Farm to Fork Strategy in 2020. In this, a “One health” is essential: protecting public health requires protecting our oceans and fish against mercury pollution.
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