Marine allergens in farmed seaweed: considerations for precautionary labelling

Abstract Seaweed aquaculture is growing and an increasing number of seaweed products is introduced on the food market. Contamination by marine allergens is a concern for the food industry and recommendations are missing on if and how products need to be labelled to assure food safety. Two species of kelp were sampled from four farms along the Norwegian coastline during two consecutive years. The samples were quantified for their content of crustacean and mollusc tropomyosin and fish parvalbumin by commercial ELISA (Enzyme-Linked Immunosorbent Assay) kits. All three seafood allergens were detected in several kelp samples with high variation, but without a specific pattern. We also studied samples in relation to their location within one farm, seeding methods, algae parts and a shifted harvesting period, with some aspects leading to differences. Samples were also analysed after blanching and fermentation at one studied farm and drying and powdering at a food processor. No major changes in allergen levels were observed after blanching and fermentation, but sample numbers might have been limiting. Homogenisation in larger quantities led to less variation between replicates, however, cross-contamination needs to be avoided. Detected marine allergens in the studied samples were below critical levels associated with an allergenic risk and would not require labelling according to the widely used VITAL (Voluntary Incidental Trace Allergen Labelling) guideline. However, this consideration is the responsibility of the food producer and needs to be based on analyses done for each batch of products as part of the general food safety evaluation.