Sea Urchin (Uni): What It Is, Raw Seafood Safety and Allergy

Sea urchin is a spiny, round sea animal, and the part people eat is the soft, golden-orange tissue inside, served in Japanese restaurants as uni. It is usually eaten raw. USDA’s SR Legacy database has no sea urchin entry, so this guide gives no USDA nutrition numbers for it. Instead it covers what uni is, what is and is not known about its composition, what CDC and FDA say about raw seafood, how sea urchin fits FDA’s allergen rules, and how it is served.

Peptide Labs does not sell sea urchin or any seafood product. This article is general nutrition information, not medical advice.

What is sea urchin (uni)?

A 2025 study in the journal Foods describes sea urchins as marine echinoderms commonly eaten as seafood in East Asia; the researchers analyzed fresh gonads, the lobes sold as uni. A 2007 case report in the Annals of Allergy, Asthma and Immunology calls sea urchin roe (uni) a Japanese and Korean delicacy. The lobes are soft and creamy, with a sweet, briny taste that varies with the species and where it was harvested.

Echinoderms are a separate group of sea animals from fish, crustaceans and mollusks, and that matters for allergen labeling, covered below. For food safety, though, the FDA Food Code counts sea urchin as seafood: its definition of fish names sea cucumber and sea urchin and the roe of such animals. Our sea cucumber guide covers the other animal in that line.

Sea urchin nutrition: what USDA does and does not list

USDA SR Legacy, the database used for nutrition numbers on this site, has no sea urchin entry of any kind. Its only roe entries come from fish, a different animal, so they are not a fair stand-in, and this guide does not borrow them. If a package of uni carries a Nutrition Facts label, that label is the number to go by.

Research gives a partial picture. The 2025 Foods study profiled the lipids in six types of Japanese sea urchin and found that triacylglycerols were the most abundant fats, that omega-3 fatty acids such as EPA were abundant in one type, and that the lipid profile differed between types. That was a lab analysis of composition, not a study of health effects. For seafood with full USDA values, see our guides to scallops, crab and oysters.

Raw sea urchin and Vibrio: what CDC and FDA say

Because uni is almost always served raw, raw seafood guidance applies. CDC says about a dozen Vibrio species cause vibriosis and that most people get it by eating raw or undercooked shellfish, particularly oysters. CDC’s prevention advice is direct: do not eat raw or undercooked oysters or other seafood, and cook them before eating. CDC lists a weakened immune system and medicines that reduce stomach acid among the factors that put people at higher risk.

FDA advises that pregnant women, young children, older adults and people with weakened immune systems avoid raw or undercooked fish and shellfish, and CDC’s guidance for pregnancy names sashimi, sushi and ceviche as examples. Restaurants following the FDA Food Code add a menu footnote stating that consuming raw or undercooked meats, poultry, seafood, shellfish or eggs may increase your risk of foodborne illness. Our guides to sushi and oysters cover the same questions for other raw seafood.

Is sea urchin shellfish? FDA allergen rules

FDA’s allergen guidance lists nine major food allergens, including fish and crustacean shellfish such as crab, lobster and shrimp. FDA interprets fish as jawless, bony and cartilaginous fish, and it states that molluscan shellfish such as oysters, clams, mussels and scallops are not major allergens. Sea urchins are echinoderms, so they fall into none of those groups, and FDA’s list does not name them. In practice, US law does not require a package to declare sea urchin as a major allergen. FDA also notes that more than 160 foods have been reported to cause allergic reactions beyond the major list.

Sea urchin allergy is documented in the medical literature. The 2007 case report described what its author called the first reported case of sea urchin roe anaphylaxis; the patient tested negative for shrimp, crab, oyster and several fish but strongly positive to fresh sea urchin roe. Studies from 2010 and 2014 identified a major yolk protein as a main allergen, and the 2014 study of five patients notes that reactions can happen the first time sea urchin roe is eaten. That study also found lab cross-reactivity with a protein in salmon roe, and a 2012 lab study reported that blood from shrimp-allergic people recognized a sea urchin roe protein. Anyone with a seafood allergy should ask an allergist before trying uni.

Is sea urchin healthy?

There is no fair way to give sea urchin a nutrition score from USDA data, because USDA has no entry for it. What can be said is that the lab work describes a fatty, omega-3-containing tissue whose makeup varies by type, that uni is usually eaten raw, which CDC and FDA flag for higher-risk groups, and that allergic reactions have been reported. Sea urchin is not on FDA and EPA’s mercury chart, so that chart gives it no group. With so little nutrition data, the practical questions are the CDC and FDA raw seafood guidance and the allergy reports in the medical literature.

How sea urchin is served

• Choose: look for firm, intact lobes with a bright color and a clean smell of the sea; lobes that look melted or smell sour are past their prime.
• In the shell: whole urchins are opened with heavy gloves and kitchen scissors around the mouth on the underside, then the lobes are lifted out with a small spoon.
• Raw: uni is served on rice, as nigiri or in bowls, which is where the raw seafood guidance above applies.
• Warm: cooks stir uni into hot pasta with butter, fold it into scrambled eggs or whisk it into sauces, which turns it rich and creamy.
• Store: keep uni cold in the refrigerator and eat it soon after you bring it home.

For a freshwater fish with full USDA values, see our guide to carp.

Frequently Asked Questions

Questions about a label? Contact us or read our Buyer’s Guide. Food comes first; follow the label and ask a healthcare provider before starting a supplement, especially if you take medicines, are pregnant or have a food allergy. These statements have not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure, or prevent any disease.

Last reviewed October 2026.

Related guides: Carp Fish: Nutrition, Mercury Group, Invasive Carp and Cooking, Sushi: Nutrition, Raw Fish Safety, Mercury and Pregnancy, Oysters: USDA Nutrition, Zinc, Raw Oyster Safety and Who Should Skip Them.