Guide · Specialty food & beverage
To let shoppers filter by gluten-free, vegan, or "contains tree nuts," each product needs those facts stored in their own fields, not buried in the description. Set up a diet field and a separate allergen field, each with a fixed list of values. Fill them from the product label. Then turn those fields into filters. On Shopify, that means metafield definitions plus filters in the Search & Discovery app. The filter is the easy part. The data is the work.
Most platforms can show a filter once the data exists. Shopify's Search & Discovery app builds custom filters from product options, metafields, and metaobjects, including text lists and true or false fields. But a filter only shows what's in those fields. If half your products have no allergen data, the filter quietly hides half your catalog.
Tags are where most stores start, and they get messy fast. "GF," "gluten free," and "Gluten-Free" turn into three different filter values. Shopify's own guidance suggests using a metafield instead of the tag filter when tags already do other jobs in your store, like collection rules.
These answer two different questions.
Keep them in two fields. Mixing "nut-free" and "contains tree nuts" in one list confuses shoppers and breaks the filter logic.
For allergens, use the FDA's list as your fixed values. Under the FASTER Act, the nine major food allergens are milk, eggs, fish, crustacean shellfish, tree nuts, peanuts, wheat, soybeans, and sesame. Sesame became the ninth on January 1, 2023.
"Gluten-free" isn't a marketing word. The FDA issued a final rule defining it for food labeling in 2013. The safe rule for a store: tag a product gluten-free only when the manufacturer's label says so. Don't infer it from the ingredient list. For allergens, copy the Contains statement from the package.
Labels also change. The FDA notes that some manufacturers changed recipes after the FASTER Act and now include small amounts of sesame where they didn't before. A label you entered two years ago may be out of date, so recheck allergen fields when a supplier sends new packaging or a new item code.
Pick one spelling for every value and write the list down. "Gluten-Free," not "GF" or "gluten free." Shopify's filter app can group several values under one label, which helps with old data. Clean values at the source are still easier to keep right.
Two Shopify limits are worth knowing. A filter shows at most 100 values on your store, and collections with more than 5,000 products don't display filters at all. Diet fields rarely hit the first limit, but a big "All products" collection can hit the second.
Your distributors' and makers' spec sheets usually carry ingredients and allergen statements. Pull them into one spreadsheet with your SKUs, map each product to your fixed values, and import. Have someone check every allergen row against the actual label before it goes live. This is the slow part, and it's worth doing once, properly.
In Shopify, the order is:
Then show the same fields on the product page near the price, so a shopper doesn't have to zoom into a photo of the label.
This is an illustrative example with made-up numbers, not a client story.
A shop with 600 products wants a gluten-free filter. Today "gluten free" appears in 140 product descriptions and as a tag on 90 products, spelled four different ways.
The shopper now sees 110 products that actually claim gluten-free, not 140 that happen to use the word.
The same fields do more than one job. They feed gift filters, the product page, Google, and AI shopping tools that read product data to answer questions like "gluten-free gift under fifty dollars." Fix the data once and every one of those gets better. More on that in product data cleanup and enrichment.
If you add an AI chat assistant to your website, it leans on the same data. When a shopper asks "Is this nut-free?", the chatbot can only answer from the diet and allergen fields you just set up. If tree nuts are missing from a product's Contains field, that product shows up when a shopper filters tree nuts out, and the chatbot tells the shopper it's fine. One gap in the data, two wrong answers.
Set one safety rule before launch. The chatbot only states what the labelled fields say, and never guesses from ingredients or descriptions. For allergy-critical questions, like cross-contact or a severe allergy, it points the shopper to the product label or to your store team. More on why in why your AI chatbot gives wrong answers.
Hauslight, the AgentHaus website assistant, answers typed and voice questions from your pages, policies, and business information. When it's connected to the relevant systems, it can use current catalog and inventory information. The diet and allergen fields in this guide are the information it needs.
If your catalog is large, your supplier sheets are inconsistent, or you'd rather not spend a month on a spreadsheet, this is the work we do for specialty food stores. AgentHaus founder Jonathan Gonsenhauser spent 20 years in the restaurant industry. Most AgentHaus projects are delivered remotely.
Get a free store check. We'll run real customer searches on your site, check how your product data reads to Google and AI tools, and tell you the three fixes we'd make first.
For a small catalog, tags can work. They pick up every spelling staff type, though, and they often do other jobs like collection rules. A dedicated field with a fixed list of values is easier to keep clean.
Start with the nine major food allergens the FDA names: milk, eggs, fish, crustacean shellfish, tree nuts, peanuts, wheat, soybeans, and sesame. Copy them from each product's Contains statement or ingredient list.
Don't. Use the gluten-free value only when the manufacturer's label makes the claim. Ingredient lists don't tell you about cross-contact in production.
Only from allergen fields filled in from the label, and it should say only what those fields say. For allergy-critical questions, it should point the shopper to the product label or to your store team.
Not necessarily. Shopify's own Search & Discovery app builds filters from metafields. Apps can add badges or nicer displays, but the product data underneath still has to be right.
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