Food and Ingredients to Avoid on a Shellfish-Free Diet

Asian soup with shellfish. Yingyode Kaewme/Eyeem/Getty Images

Shellfish allergy is often established in adulthood, and is one of the more serious food allergies for adults. Shellfish allergy is divided into two types: mollusk shellfish allergy and crustacean shellfish allergy. Shellfish are one of the most common food allergies, and as such, are included in the Food Allergy Labeling and Consumer Protection Act (FALCPA) with a limited focus. Crustacean shellfish are called out in FALCPA, but mollusk shellfish are not.

Ingredients made from, or with, crustacean shellfish in food products must be identified on product labels with an allergy warning.

Because mollusk shellfish allergens are not under requirement to be highlighted on food product labels by FALCPA, ingredient labels may not claim the presence of mollusk ingredients. Individuals with mollusk shellfish allergy or who are reactive to both types of shellfish must be very careful and err on the side of caution when selecting prepared food products. Be sure to always read ingredients labels and If unsure about a product’s safety, contact the manufacturer or avoid consumption.

Sources of Shellfish:

Many people who are allergic to one type of shellfish will be allergic to both types. For example, many folks allergic to crustacean shellfish will also be allergic to mollusk shellfish and will have to eliminate both types from their diet. If you are sensitive to both crustacean and mollusks, avoid all shellfish.

If you aren’t sure about the range of your shellfish sensitivity (for example, you’ve only reacted to clams), talk to your doctor or allergist before trying out any new types of shellfish.

People who are allergic to crustacean shellfish should avoid all crustacean shellfish, including but not limited to:

  • Barnacle
  • Crab
  • Crawfish (crayfish, crawdads, ecrevisse)
  • Krill
  • Lobster (langoustine, langouste, Moreton bay bugs, scampi, tomalley)
  • Prawns
  • Shrimp (crevette, scampi)

People who are allergic to mollusk shellfish should avoid all sources, including but not limited to:

  • Abalone
  • Clams (quahogs)
  • Cockle
  • Cuttlefish
  • Limpet
  • Mussels
  • Octopus
  • Oysters
  • Sea cucumber
  • Sea urchin
  • Scallops
  • Snails (Escargot - both sea and land snails should be avoided)
  • Squid (Calimari)
  • Surimi (imitation shellfish)
  • Whelk

Foods that May Contain Shellfish

Shellfish is often included in ethnic soups and dishes including:

  • Bouillabaisse (a French fish soup containing fish and shellfish)
  • Cuttlefish ink
  • Ceviche (fish or shellfish in an acidic citrus marinade)
  • Cioppino
  • Clamato (a clam broth and tomato juice mixture sometimes used in Bloody Mary drinks)
  • Crevette (the French term for shrimp)
  • Scampi (shrimp cooked in garlic)
  • Etouffée
  • Gumbo (often contains shellfish)
  • Paella
  • Jambalaya
  • Nam Prik (Thai fish sauce)
  • Mam Tom (Vietnamese fish sauce)
  • Surimi (imitation seafood)

Non-Food Sources of Shellfish

  • Compost or fertilizers
  • Fish food
  • Pet food
  • HemCon bandages (A wound dressing made from shrimp shells)
  • Calcium supplements made from oyster shells or coral
  • Glucosamine (an amino acid supplement used for joint regeneration)
  • Omega-3 supplements (usually made from fish, but sometimes made from shellfish)

Avoiding Shellfish in Restaurants

If you have a shellfish allergy, you should avoid certain types of restaurants because of the high risk of cross-contamination:

  • Chinese, Japanese, Thai, Vietnamese, or Malaysian restaurants. Their food items often contain a fish sauce made with shrimp.
  • Cajun or Creole restaurants. These dining venues offer meal items that often contain shrimp or other shellfish.
  • Seafood restaurants. An obvious source of potential cross-contamination. If you allergic to shellfish, avoid eating here.  
  • Some restaurants may use shellfish stock as a flavoring or base for sauces and soups. Always ask if an item contains shellfish.
  • People with severe shellfish allergies may have an allergic reaction from allergen particles released into the air during the process of steam cooking shellfish.

For general guidance on restaurant dining, use this restaurant dining guide.


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Food Allergy Research & Education:

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