Prawns and shellfish for babies: when to start, allergy and safety

Babies can eat prawns and other shellfish from around 6 months, once they've started solids. Two things matter most: cook it thoroughly, and introduce it as one of the common allergy foods. Australia's ASCIA's guide to introducing solid foods from Australia includes shellfish among the common allergy foods to introduce in the first year (by 12 months) and then keep in your baby's diet at least once a week.

Shellfish covers two groups: crustaceans, such as prawns, crab, lobster and crayfish, and molluscs, such as mussels, oysters, clams, scallops and squid. This guide covers when to start, how to cook and chop shellfish at each age, raw shellfish, mercury, and what to do if your baby reacts or chokes. For other seafood, see fish for babies.

When can babies eat prawns and shellfish?

From around 6 months, once your baby has started solids. Australian, UK and US guidance all treat shellfish as an allergy food that doesn't need to be delayed.

• Australia. ASCIA lists cow's milk, egg, peanut, tree nuts, wheat, soy, sesame, fish and shellfish as the most common allergy foods, and says to introduce them in the first year, starting with foods your family usually eats. Introducing them in the first year has been shown to reduce the risk of developing food allergy.
• UK. The NHS guide to feeding from around 6 months lists shellfish ("don't serve raw or lightly cooked") among foods that can trigger allergic reactions. It says to introduce these one at a time, in very small amounts, from around 6 months, and to keep offering them once tolerated.
• US. The AAP's allergen guide lists fish and shellfish among highly allergenic foods to introduce once your baby has managed a few lower-risk first foods, and says newer research has found no benefit in delaying them. The CDC's guide to introducing solid foods says to introduce potentially allergenic foods, including shellfish, when you introduce other foods.

Shellfish also brings useful nutrients. The NHS fish and shellfish page says shellfish is low in fat and a source of selenium, zinc, iodine and copper, and that mussels, oysters, squid and crab also provide some long-chain omega-3 fats.

How do I introduce shellfish as an allergen?

Treat each new shellfish like any other allergy food:

1. Pick a good time. Offer it when your baby is well and you can watch them for the next couple of hours. Australia's ASCIA says allergic reactions usually happen within minutes to two hours.
2. One new allergy food per meal. Australia's ASCIA says this makes it easier to spot which food caused a reaction.
3. Start small. The NHS suggests very small amounts, and the AAP suggests small tastes, increased gradually if there's no reaction. Mix a little finely minced, well-cooked prawn into a food your baby already eats, such as vegetable mash.
4. Keep it going. Once it's tolerated, Australia's ASCIA says to include it at least once a week, in age-appropriate servings, which may reduce the chance of an allergy developing.

Crustaceans and molluscs are different groups, so introducing prawns doesn't introduce mussels or squid. Australia's ASCIA's seafood allergy FAQ explains that the allergy proteins in one seafood group can be very different from those in another, so a person can be allergic to fish only, shellfish only, or both. It also says seafood allergy is more common in teenagers and adults than in very early childhood.

If your baby has eczema or a diagnosed food allergy, the NHS guide to food allergies in babies suggests talking to your GP or health visitor before introducing allergy foods. Australia's ASCIA's advice is that these babies should still have the common allergy foods in the first year. Introducing allergens has the full plan.

How should shellfish be cooked for babies?

Thoroughly, every time. The CDC's safer food choices for children under 5 lists shellfish cooked until the shells open, or until the flesh is pearly or white and opaque, as the safer choice. It says young children's immune systems are still developing, and that food poisoning can lead to diarrhoea and dehydration.

1. Buy it cold. The FDA's seafood safety guide says to buy seafood that's refrigerated or on a thick bed of fresh ice, and that it should smell mild, not sour or like ammonia.
2. Thaw frozen shellfish in the fridge overnight, as the FDA suggests.
3. Check live shellfish. The NHS says to throw away mussels, oysters, clams or other live shellfish with cracked or broken shells, or with open shells that don't close when tapped.
4. Peel prawns and remove the heads, legs, shells and tails before or after cooking.
5. Cook until done. The FDA says prawns, scallops and lobster are cooked when the flesh is firm, pearly and opaque, and clams, mussels and oysters when the shells open; throw out any that don't open.
6. Skip the salt. The NHS list of foods to avoid says not to add salt to your baby's food or cooking water, or use stock cubes or gravy.

Are ready-cooked prawns okay?

Heat them until steaming hot first. Food Standards Australia New Zealand lists chilled cooked prawns among higher-risk ready-to-eat foods for vulnerable groups, which include newborn babies, and suggests seafood that's freshly cooked or thoroughly reheated until steaming hot. It says to use it straight away or refrigerate leftovers and use them within a day.

Can babies eat raw shellfish, oysters or sushi?

No. The NHS says raw or lightly cooked shellfish, such as mussels, clams and oysters, can increase the risk of food poisoning, so it's best not to give it to babies. Its fish and shellfish page says raw shellfish, particularly oysters, can carry viruses such as norovirus, and that young children should avoid raw or lightly cooked shellfish.

• Raw oysters. The FDA says children should avoid raw oysters, even ones treated after harvest, and that freezing doesn't kill all harmful germs.
• Sushi, sashimi and ceviche. The CDC lists raw or undercooked fish or shellfish, including these, as riskier choices for children under 5. FSANZ lists raw oysters, sushi, sashimi, ceviche, smoked seafood and chilled cooked prawns as higher-risk foods for vulnerable people.

The NHS also notes that some toxins found in shellfish don't break down during cooking, so thorough cooking lowers the risk from germs but can't remove every hazard.

How do I prepare prawns and shellfish at each age?

Cooked prawns and squid are firm and springy, more like meat than flaky fish, so the texture needs extra care. The CDC's choking hazards list includes tough or large chunks of meat, and New Zealand's Ministry of Health, in its advice on reducing food-related choking, says pieces of cooked meat can get wedged in the airway. For children aged 1 to 6 at early learning services, it suggests mincing, shredding or chopping meat into pieces of about 8 mm by 8 mm.

A few practical points:

• Mince rather than slice. A whole prawn or a ring of squid is hard for a baby to break down. Mince or chop it and mix it through something soft.
• Pick crab meat carefully for shell. The NHS says brown crab meat contains cadmium, which can affect bones and kidneys in large amounts, so white crab meat is the better choice.
• Watch packaged foods. Australia's ASCIA's shellfish dietary guide lists prawn crackers, seafood extender, oyster sauce and squid ink among foods that may contain shellfish. Prawn crackers are also like the chips and snack foods the CDC lists among choking hazards.
• Skip battered and fried seafood. Australia's Pregnancy, Birth and Baby lists processed foods with fat, sugar or salt, such as chips and fried foods, as unsuitable for babies.

For how textures progress overall, see food textures by age.

Do prawns and shellfish contain mercury?

Shellfish sits at the low end for mercury in the guidance we checked.

• US. The FDA's advice about eating fish counts shellfish as fish, and lists clams, crab, crawfish, lobster, oysters, scallops, shrimp (prawns) and squid among its lowest-mercury best choices. For children aged 1 to 11, it suggests 2 servings a week from that list, with a serving of about 1 ounce (about 30 g) at ages 1 to 3.
• Australia. The FSANZ mercury advice sets limits for shark (flake), billfish such as swordfish and marlin, orange roughy and catfish. It doesn't name shellfish.
• UK. The NHS says there are no maximum amounts recommended for white crab meat or other types of shellfish; brown crab meat is the exception, because of cadmium.

Rotating shellfish with lower-mercury fish is an easy way to add variety. Fish for babies has the full mercury table.

What does a shellfish allergy reaction look like?

Australia's ASCIA's anaphylaxis FAQ separates mild to moderate signs from anaphylaxis, the most severe type of allergic reaction.

Australia's ASCIA classes lip swelling as a mild to moderate sign, while the NHS urgent-help guide lists swollen lips, tongue or throat among the reasons to call an ambulance, so this guide treats sudden lip swelling as an emergency. A mild reaction can come before anaphylaxis, so keep watching. Australia's ASCIA's seafood FAQ says reactions to seafood usually appear within minutes, although delayed reactions can happen, particularly after shellfish.

Redness or hives only around the mouth, with no other signs, is not usually an allergic reaction, according to Australia's ASCIA. Offer the food again when your baby is well.

These steps follow the Australia's ASCIA first aid plan for anaphylaxis. For hives, face or eye swelling, or vomiting with normal breathing, stop giving the food, stay with your baby, watch closely and get medical help today. Australia's ASCIA says to get specialist advice before offering that food again, and to keep introducing the other allergy foods.

What if my baby vomits a few hours later?

Repeated vomiting that starts hours after a food can be a different type of reaction. Australia's ASCIA's FPIES FAQ describes food protein-induced enterocolitis syndrome as a delayed gut food allergy that usually causes repeated vomiting one to four hours after the trigger food, and some babies become floppy, pale and cold. It says any food can trigger it; in babies the most common triggers are rice, oat, cow's milk and egg, while seafood is the most common trigger in adults. Get medical help today for repeated vomiting after a food, and call 999 if your baby becomes pale and floppy.

What should I do if my baby chokes?

If your baby can't breathe, cough or cry, shout for help and call 999. The NHS first-aid steps for a choking baby are up to 5 back blows, then up to 5 chest thrusts, repeated until help arrives; if your baby becomes unresponsive, start CPR and follow the call-taker's instructions. Get medical help afterwards, even if the food came out.

Gagging is common while babies learn to manage new textures; choking vs gagging explains the difference. The Royal Children's Hospital Melbourne in Australia recommends that anyone caring for children does a first-aid course and learns infant CPR.

A short note of which shellfish your baby has tried, how it was cooked and how they got on makes it easy to keep allergy foods going each week. If your baby reacts, note the time, the food and what you saw; a photo of any rash helps the doctor.

When should I get help?

Call 999 now if your baby:

• has sudden swelling of the lips, tongue or throat
• has difficult or noisy breathing, a wheeze or a persistent cough
• has a hoarse voice or cry, or becomes pale, floppy or drowsy, or collapses
• is choking and can't breathe, cough or cry
• has had no wet nappy or wee for 12 hours

Get medical help today if your baby:

• has hives or welts beyond the mouth area, or swelling of the face or eyes, with normal breathing (stop the food and watch closely for anaphylaxis signs)
• vomits after eating shellfish, including repeated vomiting that starts a few hours later
• needed back blows or chest thrusts, even if they now seem well
• has diarrhoea or vomiting with fewer wet nappies than usual (see signs of dehydration)

Talk to your GP or health visitor if:

• your baby has eczema or a diagnosed food allergy and you're planning to introduce shellfish
• your baby has reacted to one type of seafood and you'd like advice on others
• you're unsure which seafood suits your family's usual meals