Shellfish

Crustacean Shellfish & Mollusks

Crab, Lobster, Shrimp

• 2.5% of Americans are allergic to Crustacean Shellfish.
• Shellfish allergy is not usually found in kids under 6 years of age.
• It is rare to develop tolerance and this is usually a lifelong allergy.
• Shellfish protein can act as an aeroallergen that provokes anaphylaxis through inhaled cooking aroma and steam.
• Shellfish cross-react with dust mites and cockroach dander.
• Astaxanthin is an algae eaten by shellfish and other animals and the reason for the shell coloring – it is also the cross-reactor between Crustaceans (and it appears in farm-raised fish!).

Relevance to Food Service

• Be aware that shellfish allergy can be triggered by certain vitamins and supplements.
• Aggressive, physical cleaning (with hot soapy water) prior to sanitizing all food contact surfaces, including high-touch areas (chair backs, table edges) after each use.

Shellfish as Allergen

A common allergen that can cause severe reactions in some individuals. Shellfish allergies are caused by proteins found in shellfish, including crustaceans (such as shrimp, crab, and lobster) and mollusks (such as oysters, clams, and mussels). The proteins that cause allergic reactions in shellfish are heat-stable, meaning they are not destroyed by cooking, and can persist even in processed food products.

Crustacean allergens are found in the flesh, exoskeleton (shell), and digestive gland of crustaceans. Mollusk allergens are found in the flesh and sometimes in the digestive gland of mollusks.

In addition to the allergenic proteins, some individuals may also be allergic to other components of seafood, such as histamines, which are naturally occurring compounds found in some types of fish that can cause allergic reactions.

The scientific designations of the allergenic components of shellfish vary depending on the type of shellfish. However, some of the most well-known shellfish allergens include:

• Crab: Crustacean Tropomyosin (CRTM)
• Lobster: Tropomyosin (TM)
• Shrimp: Tropomyosin (TM)
• Oyster: Oyster allergen (Oyster All)
• Clam: Myosin light chain (MLC)

These allergens are proteins that are found in various tissues of shellfish, such as the flesh and the exoskeleton, and can cause an allergic reaction in some individuals.

It is important to note that shellfish allergens can vary between species and even between individuals, and it is possible for an individual to be allergic to one type of shellfish but not to another. Additionally, cross-reactivity between different types of shellfish can occur, so it is important to talk to your doctor about your specific allergy and any possible cross-reactivity.

Shellfish can be present in unexpected products, such as:

1. Seasonings and flavorings: Some seasonings, such as Old Bay, contain shrimp or crab extract, which can be an allergen for individuals with shellfish allergies.
2. Salad dressings and sauces: Some salad dressings and sauces, such as Thousand Island and Worcestershire sauce, contain anchovy extract, which can be an allergen for individuals with shellfish allergies.
3. Lip balms: Some lip balms contain seafood-based ingredients, such as salmon oil or pearl extract, which can be an allergen for individuals with shellfish allergies.
4. Supplements: Some dietary supplements, such as Omega-3 supplements, contain fish oil, which can be an allergen for individuals with shellfish allergies.
5. Processed foods: Some processed foods, such as canned soups and sauces, may contain shellfish-based ingredients, such as shrimp or crab flavoring.

Astaxanthin is a pigment that is found in various seafood, including salmon, trout, crab, lobster, and shrimp. Although astaxanthin is not considered a major allergen, some people may experience an allergic reaction after consuming seafood that contains this pigment.