How to Convert a Recipe for Food Allergies

Converting a recipe for a food allergy is a different task from substituting for a missing ingredient. A swap that tastes right can still be unsafe if it brings in another allergen, if a packaged ingredient hides the original one, or if the safe version picks up traces from a shared spoon. This article covers the method; the person with the allergy and their allergist set the rules, and the label on each product is the final word.

Know the nine and how labels show them

FDA lists nine major food allergens: milk, eggs, fish, crustacean shellfish, tree nuts, peanuts, wheat, soybeans and sesame. Sesame joined the list under the FASTER Act, effective January 1, 2023. Products already on shelves before that date did not have to be relabeled, so an older package may not flag sesame.

On a packaged food, each major allergen must be named at least once, either in parentheses after the ingredient, as in “lecithin (soy)” or “flour (wheat)”, or in a “Contains” statement next to the ingredient list. Tree nuts, fish and shellfish must be named by type. A few gaps matter at home:

• “May contain” and “made on shared equipment” lines are voluntary. FDA does not require them, so their absence does not prove a product is free of cross-contact.
• Highly refined oils are exempt from the labeling law, as are foods sold unpackaged at a counter.
• The definitions changed in 2025. FDA’s January 2025 guidance counts goat and sheep milk as “milk” and duck or quail eggs as “eggs”, and it removed coconut from the tree nut list, FARE reports. Coconut still appears in the ingredient list.

Where the allergens hide in ordinary recipes

Most slips come from compound ingredients, where the allergen sits inside something else on the list.

Ingredient in the recipe	Allergen inside
Soy sauce, tamari	Soy; regular soy sauce is also brewed with wheat
Classic Worcestershire sauce, Caesar dressing	Fish (anchovies)
Fish sauce	Fish
Oyster sauce	Shellfish (oysters)
Pesto	Tree nuts (pine nuts), milk (cheese)
“Nondairy” creamer or topping	Often milk, as caseinate
Ghee, butter oil	Milk
Vegan mayonnaise	Often soy protein
Hummus, many dressings and spice crusts	Sesame (tahini or seeds)

University Hospitals’ milk allergy diet sheet adds less obvious milk sources such as caramel and butter flavorings, nougat and many processed meats. The same habit applies to every allergen: read the full ingredient list of each packaged item, every time, since recipes change without notice.

Swaps that only move the allergen

The commonest conversion error is a substitute that removes one allergen and adds another. Before using any swap, check what it is made from.

Swap	Removes	Adds
Tahini for peanut butter	Peanut	Sesame
Soy nut butter for peanut butter	Peanut	Soy
Almond or cashew butter for peanut butter	Peanut	Tree nuts
Almond flour for wheat flour	Wheat	Tree nuts
Almond or cashew milk for cow’s milk	Milk	Tree nuts
Soy milk, tofu or soy yogurt for dairy or eggs	Milk, egg	Soy
Seitan for tofu or tempeh	Soy	Wheat
Roasted peanut oil for toasted sesame oil	Sesame	Peanut
Mushroom “oyster” sauce for oyster sauce	Shellfish	Soy, often wheat

The peanut butter guide points to sunflower seed butter at 1:1 as the option outside the nine major allergens; the tahini guide gives the same answer when both sesame and tree nuts are excluded. Coconut aminos replace soy sauce without soy or wheat, with a pinch of salt added, per the soy sauce guide.

A worked conversion: sesame-peanut noodles

A typical recipe for four: 8 oz wheat noodles, ¼ cup peanut butter, 3 tbsp soy sauce, 1 tbsp toasted sesame oil, 1 tbsp rice vinegar, 1 tsp fish sauce, sesame seeds to finish. Converting it for a child with peanut and sesame allergies:

1. List every allergen, including inside compounds. Peanut (peanut butter), sesame (oil, seeds), soy and wheat (soy sauce, noodles), fish (fish sauce). Only peanut and sesame must go; the rest stay if the child tolerates them.
2. Peanut butter. Sunflower seed butter at the same ¼ cup. Tahini and roasted peanut oil are both out, since each carries one of the two allergens. Unsweetened sunflower butter keeps the sauce savory; a sweetened one needs a little extra vinegar.
3. Toasted sesame oil. The sesame oil guide lists perilla oil at 1:1 as a toasted, nutty finishing oil; otherwise use a neutral oil and accept a plainer taste. Check that the neutral oil bottle is not a sesame blend.
4. Garnish. Replace sesame seeds with toasted sunflower seeds or sliced scallion for crunch and color.
5. Read the remaining labels. Confirm the soy sauce, vinegar and noodles carry no sesame or peanut statement, and check the “may contain” lines with the family’s allergist’s advice in mind, since those lines are voluntary.

If the child also avoided soy and wheat, the next round would be rice noodles, coconut aminos with salt for the soy sauce, and the fish sauce guide for a soy-free route around the fish sauce.

Cross-contact in a home kitchen

FARE defines cross-contact as proteins from one food mixing into another in amounts too small to see, and stresses that cooking does not remove an allergen. Its handout gives the practical rules:

• Cook the allergy-safe food first and keep it covered, away from anything that could splatter.
• Use utensils, boards and pans washed with soap and water; some families keep a separate, color-coded set.
• Wash hands with soap and water after touching an allergen. FARE’s cleaning page cites a study in which plain water left peanut allergen on 3 of 12 hands and antibacterial sanitizer on 6 of 12.
• If a mistake happens, start again. Picking the shrimp off a salad or scraping peanut butter off bread leaves enough protein behind to cause a reaction.

Common mistakes

• Swapping tahini into a nut-free recipe. It removes peanuts but adds sesame, a US major allergen since 2023.
• Using tamari as a “safe” soy sauce. It is still soy, and not every brand is wheat-free.
• Trusting “nondairy” on a label. Caseinate is a milk protein that can sit in a nondairy product.
• Reading only the front of the package. The allergen statement and ingredient list are on the back, and formulas change.
• Wiping a knife instead of washing it. Residue on a wiped blade transfers enough protein to make the safe food unsafe.
• Treating hand sanitizer as hand washing. It does not remove allergen proteins; soap and water do.

For specific swaps, see going dairy-free, egg substitutes and gluten-free flours.