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· 4 min read
How to Check a Recipe for Hidden Allergens
Heshan Fernando
Co-founder & COO
Someone coming for dinner has a wheat allergy, so you plan a rice dish. Then you use soy sauce, which in most standard varieties contains wheat, and a stock cube, which frequently contains both celery and milk derivatives.
The obvious allergens are easy. It’s the ingredients that look like single things and aren’t that cause the problems.
Where allergens hide
Soy sauce — most standard varieties contain wheat. Tamari is usually the wheat-free alternative, but check the specific bottle.
Stock cubes and bouillon — celery is extremely common, and milk derivatives appear frequently. Both are declarable allergens in most regimes and both surprise people.
Oils and spice blends — sesame oil is obviously sesame, but sesame and nuts also appear in blended oils and in spice mixes without being the headline ingredient.
Worcestershire sauce — contains fish (anchovy), which catches vegetarians and fish-allergic guests alike.
Marzipan, pesto, some breads — nuts, where the recipe name doesn’t mention them.
“Natural flavouring” — a category label that can cover a range of sources.
The 14 major allergens that must be declared in the UK and EU are cereals containing gluten, crustaceans, eggs, fish, peanuts, soybeans, milk, nuts, celery, mustard, sesame, sulphur dioxide, lupin and molluscs. Celery, mustard, lupin and sulphites are the ones people forget exist.
Why this checks ingredients, not products
An ingredient list tells you what “soy sauce” typically contains. It cannot tell you what the specific bottle in your cupboard contains, because formulations vary by brand and change over time.
For a preference or a mild intolerance, an ingredient-level check is a reasonable working tool. For anyone with a serious or anaphylactic allergy, it is not sufficient. Read every package label in your kitchen, including the “may contain” warnings, and if there’s any doubt, don’t serve it.
Cross-contamination is a separate problem
Ingredient checking says nothing about preparation. Shared chopping boards, a knife used for bread then for salad, a fryer that cooked breaded food, flour dust in the air — all of these matter enormously for a serious allergy and none appear in a recipe.
If you’re cooking for someone with a severe allergy, talk to them about how they need it prepared. They will know, they will have thought about it far more than you have, and they would far rather be asked.
| Ingredient | Hidden Allergen |
|---|---|
| Soy sauce | Wheat (most varieties) |
| Stock cube | Celery, often milk |
| Worcestershire sauce | Fish (anchovy) |
| Spice blends | Sesame, nuts, mustard |
| Some breads | Sesame, milk, soy |
Common mistakes to avoid
- Assuming a recipe is safe because no allergen appears in the title.
- Checking the main ingredients and skipping the sauces and stocks.
- Relying on a previous purchase of the same product — formulations change.
- Ignoring “may contain” warnings, which exist because cross-contamination is real.
- Not asking the guest, who is the best-informed person in the conversation.
How to do it with Recipe Allergen Checker
The Recipe Allergen Checker flags likely and hidden sources across the 14 major allergens, in your browser.
- Paste the full ingredient list, including sauces, stocks and anything pre-made.
- Read the hidden sources as well as the obvious ones.
- Verify every flag against the actual packaging in your kitchen.
- Ask your guest about preparation, not just ingredients.
Other food and kitchen tools are in the tools directory.
Frequently asked questions
Can this be relied on for a serious allergy?
No. It works from ingredient names, not from the specific products in your kitchen. For an anaphylactic allergy, read every package label including “may contain” warnings — the packaging is the only authority.
Which hidden sources catch people out most?
Wheat in soy sauce, celery and milk in stock cubes, fish in Worcestershire sauce, and sesame or nuts in oils and spice blends. All look like single-ingredient items and aren’t.
What about cross-contamination?
This checks ingredients, not preparation. Shared utensils, boards and fryers matter enormously for serious allergies and can’t be assessed from a recipe.
Final thought
Check the sauces first — they’re where the allergens hide. Then read the actual packaging, because that’s the only thing that describes what’s in your kitchen tonight.