Shellfish: Managing a Common Allergen

Regulatory Requirements for Shellfish Allergens

Shellfish, including crustaceans and mollusks, must be declared as allergenic ingredients in food products in accordance with the EU Directive (EC 1829/2003 and EC 1830/2002). Fish and crustaceans are among the eight major allergens that must be declared in the USA and many other countries. Mollusks must also be labeled in South Africa.

Prevalence of shellfish allergies

Seafood allergies are quite common, but their prevalence varies significantly by region. People living in coastal areas, where seafood consumption is higher, are more frequently affected than those in inland regions. This variation makes general risk management challenging.

Crustaceans

The crustacean genus includes prawns, crabs, shrimp, lobster, crayfish, krill, crawfish, and large crabs. Consuming crustaceans can trigger severe allergic reactions, impacting the skin, gastrointestinal tract, and respiratory system. The muscle protein tropomyosin, a heat-stable protein constituting 20% of the total protein content in crustaceans, is responsible for these reactions. Crustacean allergies often develop in adulthood and can persist for life. High degrees of sensitization are common, necessitating meticulous cleaning of food production lines to avoid residues. The effectiveness of cleaning can be examined with lateral flow swab tests, and food can be analyzed using ELISA and PCR tests.

Mollusks

The mollusk genus includes mussels, snails, and cephalopods (such as cuttlefish and squids). Popular in coastal regions, mollusks like blue mussels, oysters, and octopus can cause allergic reactions in some individuals. Similar to crustaceans, the primary allergen in mollusks is the muscle protein tropomyosin, which can also result in cross-sensitivities. High degrees of sensitization are possible, meaning even trace amounts can trigger severe reactions.