Fish and seafood are among the most common food allergens, along with nuts, eggs, cow’s milk, fruit, soya and other foods. It is estimated that approximately 2.2% of the global population is affected by an allergy to fish, while around 2% of individuals are allergic to seafood. The prevalence of allergies to fish and seafood is related to their consumption demonstrating an higher incidence of allergies to fish and seafood in regions where these foods are consumed at a relatively high rate, such as Scandinavia.
In accordance with EU Directive 2007/68/EC and Regulation 1169/2011, fish, crustaceans and molluscs are defined as allergic ingredients, which require an appropriate labelling.
The current directive does not define any thresholds or action levels for labelling, which results in a zero-tolerance policy. Due to the diverse process steps, which include the trade in raw materials, their storage and the production processes, cross-contamination cannot be ruled out with certainty throughout the entire process.
Allergies to fish and seafood
In case of fish and seafood allergies, the onset of allergic symptoms is not limited to the comsumption of these foods. The symptoms can also manifest when raw seafood or fish is processed, as well as a result of inhaling steam during cooking. In addition, contact allergies can also be triggered by products containing fish or seafood ingredients, such als creams and other cosmetics. Allergic reactions include itching, redness of the skin, gastrointestinal distress, and, in more severe cases, respiratory compromise or anaphylaxis.
With 33,600 described species, fish exhibit greater diversity than any other group of vertebrates. In numerous countries, fish, whether freshwater or saltwater, constitute a dietary staple. In addition to its high protein content, fish is a rich source of omega-3 fatty acids, healthy fats, iodine and calcium. These attributes contribute to the observed increase in the consumption of fish and fish products.
In addition to fish, the classification of seafood also encompasses molluscs and crustaceans.
Crustaceans are classified within the Arthropoda, a group that encompasses approximately 44,000 species. The most common cause of food-related allergic reactions is hypersensitivity to crustaceans, including prawns, lobsters, crayfish, and crabs. Crustaceans are the third most common cause of food-related anaphylaxis. The majority of individuals who develop allergies to crustaceans do so at a later age.
Snails (Gastropodae), mussels (Bivalvia) and cephalopods (Cephalopodae) belong to the molluscs family. Molluscan species such as squid, calamari, oysters and snails are frequently used in the preparation of Asian cuisine, as well as in salads, soups and various sauces. In general, food allergies to molluscs are uncommon. However, even small amounts of the heat-stable protein are allergenic, which is why sensitive detection methods are required.
Detection of fish, crustaceans and molluscs DNA
For this purpose, CONGEN has developed a real-time PCR test for the direct qualitative detection and differentiation of a specific DNA sequence of fish, crustaceans and molluscs in food and feed. The SureFood® ALLERGEN 4plex SEAFOOD (Art. No. S3405) kit is compatible with all commercially available real-time PCR devices that are capable of detecting at least four reporter dyes simultaneously.
For further quantification, CONGEN offers real-time PCR Kits, such as SureFood® ALLERGEN Fish (Art. No. S3610) and SureFood® ALLERGEN Molluscs (Art. No. S3613).