Which allergen should I introduce to my baby first?

Peanut and egg are the most-studied and are often introduced first, around 6 months. After they go well, work through the others one at a time.

The Top 9 Baby Food Allergens (and How to Introduce Each)

Q: What are the 9 major food allergens?

In the U.S. the nine major allergens are milk, egg, peanut, tree nuts, soy, wheat, sesame, fish, and shellfish. Sesame became the official ninth major allergen in 2023.

Q: Is sesame a top allergen?

Yes. Sesame was added as the ninth major U.S. food allergen under the FASTER Act, effective January 2023. Thinned tahini is an easy baby-safe form.

Q: How many baby food allergens are there?

Nine foods account for the large majority of allergic reactions, but tree nuts, fish, and shellfish are each categories with several members. Introduce each specific food on its own.

01The big nine at a glance

Allergen	Baby-safe form	Quick note
Peanut	Thinned smooth peanut butter	Best-studied; often introduced first
Tree nuts	Thinned nut butters	Almond, cashew, walnut, hazelnut, pecan, pistachio
Egg	Well-cooked / scrambled	Cook thoroughly
Milk	Yogurt & cheese	No cow's milk as a drink before 12 months
Soy	Tofu, edamame purée	Soft and smooth
Wheat	Iron-fortified cereal, soft pasta	Good early iron source
Sesame	Thinned tahini	The newest major allergen
Fish	Cooked, flaked, deboned	Low-mercury options
Shellfish	Cooked, finely chopped	Often introduced a bit later

02How to introduce each one

Peanut & tree nuts

Never whole nuts or thick globs — choking hazards. Use smooth, thinned nut butters. Start with peanut, then work through the seven nuts one at a time. This is exactly the cluster Tiny Acorn is designed to simplify.

Egg

Cook eggs thoroughly (scrambled or baked into foods). Offer a small amount of well-cooked egg and watch for a reaction.

Milk

Introduce dairy through yogurt and cheese rather than cow's milk as a drink, which isn't recommended before 12 months. Plain whole-milk yogurt is an easy first taste.

Soy

Silken or soft tofu mashed, or a smooth edamame purée, makes soy easy to introduce.

Wheat

Iron-fortified infant cereals and well-cooked, soft pasta are simple ways in — and a helpful source of iron.

Sesame

Thin a little tahini (sesame paste) with water or stir into purée. Treat it like a nut butter — never thick globs.

Fish & shellfish

Offer well-cooked, flaked, carefully deboned fish (low-mercury choices like salmon). Shellfish is cooked and finely chopped, and many families introduce it a little later.

03The general method

One new allergen at a time, earlier in the day.
Start small, then offer a bit more if there's no reaction after ~10 minutes.
Watch for about 2 hours while baby is healthy and you're home.
Keep tolerated foods in rotation — about twice a week.

For the full walkthrough and a sample order, see how to introduce allergens to your baby.

Frequently asked questions

What are the 9 major food allergens?

Milk, egg, peanut, tree nuts, soy, wheat, sesame, fish, and shellfish. Sesame became the official ninth major U.S. allergen in 2023.

Which allergen should I introduce first?

Peanut and egg are the most-studied and are often first, around 6 months. After they go well, work through the others one at a time.

Is sesame a top allergen?

Yes — sesame was added as the ninth major allergen under the FASTER Act, effective January 2023. Thinned tahini is an easy baby-safe form.

How many baby food allergens are there?

Nine foods cause most reactions, but tree nuts, fish, and shellfish are each categories with several members. Introduce each specific food on its own.

The top 9 baby food allergens

On this page