Processing methods may alter the content of hazards; in particular, the iodine content can be reduced. However, some products may still contain excessively high levels of iodine after processing. Since a high intake of iodine may cause health concerns, consumers should be appropriately informed about the possible risk of such products, to enable them to make an informed choice. Dietary advice and labelling are possible tools to be used for this information.
Other hazards should also be considered. Examples of other possible hazards in seaweed discussed in the literature are Norovirus, Vibrio, Clostridium spp., Aeromonas spp., E. coli, S. aureus, Hepatitis A virus, Hepatitis E virus, Campylobacter spp., Shigella spp., yeast and moulds, various toxins, anti-nutrients, persistent organic pollutants, microplastic, radionuclides, nickel, aluminium, dioxins, polychlorinated biphenyls, brominated flame retardants, polycyclic aromatic hydrocarbons, fluorine, pesticide residues, pharmaceuticals, micro-and nanoplastics, and perfluoroalkyl substances.
It should be borne in mind that data on food hazards in seaweed are currently sparse. Knowledge about food safety in seaweed is increasing, but more data is needed to enable proper risk assessments. The type, level, and ranking of food hazards in seaweed in Nordic countries may change in the future, as more research produces new data, and conditions may be affected by climate change, such as increased sea temperature. New seaweed species may also be introduced into Nordic waters.
The data on heavy metals and iodine in seaweed collected from the Nordic countries, is limited. For most seaweed species several samples have been analysed, but for some, only very few. The amount of data will increase considerably when the data collected from the EU monitoring becomes available.
The fast-developing seaweed market in the Nordic countries is in an innovative phase, and the level of consumption of seaweed products is not yet known but is probably increasing. The lack of data on both food hazards and consumer intake makes it difficult to perform proper risk assessments that include both consumption and levels of hazards.
The EU Commission has asked EFSA to deliver a scientific report by 2022, with a consumer exposure assessment for arsenic, cadmium, lead, mercury, and iodine in seaweed, and also an overview of the available occurrence data of these components.
Risk management, including development of legislation
Legislation on seaweed for use as food is sparse, both globally and in Europe. In risk management and future development of regulations and standards on food safety of seaweeds, it is important to take into account the biology and the properties of these organisms.
Compared to other organisms used as food, such as terrestrial plants like vegetables, fruits and mushrooms, seaweeds have different properties and growth environments and might also differ in terms of bioavailability of the food hazards. In addition, seaweed may be consumed in different amounts and patterns than other foodstuffs. The great variation between seaweed species, the effect of age, growing conditions, and processing methods on the levels of food hazards should also be considered.
The authors of this report strongly recommend development of a harmonised legislation on food safety in seaweed, in which seaweed should be classified as a specific group of foodstuffs, with subgroups for different seaweed species.
In the near future, the EU Commission is expected to evaluate risk management options for heavy metals and iodine in seaweed. This work will be welcomed by the food authorities in Denmark, the Faroe Islands, Iceland, Norway, and Sweden.