Voluntary Allergen Warnings in the US: May Contain Statements

If you sell food products through a Shopify store and ship to US customers, you have almost certainly wrestled with the question of whether to add a "may contain" statement to your product listings. These short phrases — may contain peanuts, produced in a facility that also processes tree nuts — appear on countless food labels, yet very few food business owners understand the legal framework that governs them. That lack of clarity leads to real problems: either businesses omit warnings they should include, or they plaster vague disclaimers everywhere and accidentally undermine the trust of the customers they most need to protect.

Under the Food Allergen Labeling and Consumer Protection Act (FALCPA), passed in 2004 and later expanded by the FASTER Act of 2021, manufacturers must declare the presence of any of the nine major US allergens as ingredients. However, the law is almost entirely silent on what businesses should do when allergens are present due to shared equipment, shared production lines, or cross-contact during storage and transit. This gap between mandatory labeling and voluntary warnings is where most of the confusion lives.

In this post, you will learn exactly what voluntary allergen warnings are, how the FDA approaches them, when you should use them, what language is legally safe and what is not, and how to implement them consistently across your Shopify product catalog.

What FALCPA Actually Requires — and What It Leaves Out

FALCPA mandates that the nine major US allergens — milk, eggs, fish, shellfish, tree nuts, peanuts, wheat, soybeans, and sesame — must be declared whenever they are intentional ingredients in a packaged food product. The declaration must appear either in the ingredients list using the food's common name or in a separate "Contains" statement immediately following the ingredients list. For example, a product containing lecithin derived from soy must either say "soy" in parentheses after "lecithin" in the ingredient list or include a line that reads Contains: Soy. These requirements apply to food labels on physical packaging sold in the US.

What FALCPA does not require is any disclosure about cross-contact allergens — allergens that are not intentional ingredients but may be present because of manufacturing environment, shared equipment, or adjacent production lines. The FDA acknowledges that cross-contact is a genuine food safety risk, particularly for the estimated 32 million Americans living with food allergies, but the agency has historically left the decision to include advisory statements to manufacturers' discretion. This is the voluntary nature of "may contain" warnings: they are not legally required, but they are also not regulated in the same way that mandatory declarations are.

For Shopify sellers, this creates a practical challenge. If you manufacture your own products, you need to assess your facility's cross-contact risks and decide whether a voluntary statement is warranted. If you are a reseller or white-label operator, you need to understand what the original manufacturer's facility practices actually are before repeating or modifying any advisory statements in your online product listings. Getting this wrong in either direction — overstating or understating risk — carries serious reputational and legal consequences.

The Nine Major Allergens Under US Law (Post-FASTER Act)

Before diving into voluntary warning language, it is worth being precise about which allergens US federal law currently covers, because this changed relatively recently. The original FALCPA list from 2004 covered eight allergens: milk, eggs, fish, shellfish, tree nuts, peanuts, wheat, and soybeans. The FASTER Act of 2021 added sesame as the ninth major allergen, with full compliance required from January 1, 2023. Any Shopify food product sold to US customers that contains sesame — including ingredients like tahini, sesame oil, or benne seeds — must now include a mandatory declaration.

It is important to understand that "tree nuts" is a category, not a single allergen. If your product contains almonds specifically, your label must identify the specific tree nut — "almonds" — either in the ingredient list or in the Contains statement. The same applies to fish and shellfish: you must name the species. A label that simply says "Contains: Fish" when the product contains cod is technically non-compliant. This level of specificity matters when you are writing product descriptions for your Shopify listings, because what appears online should be consistent with what appears on your physical packaging.

For businesses that are new to the US market or have recently reformulated products, conducting a full allergen audit before updating your Shopify catalog is a sensible first step. List every ingredient, trace each to its supplier specification sheet, identify the manufacturing facility risks, and only then write your allergen declarations and any voluntary advisory statements. Attempting to write compliant labels from memory or from ingredient names alone is one of the most common and costly mistakes food businesses make when entering the US market.

What "May Contain" Statements Actually Mean Legally

In the United States, there is currently no federal standard that defines what phrases like may contain, produced in a facility that also handles, or made on shared equipment with actually mean from a risk quantification standpoint. The FDA has acknowledged in guidance documents that advisory statements are voluntary and that there is significant inconsistency in how they are used across the industry. Some manufacturers use them to indicate a genuine, measurable cross-contact risk; others use them as a broad liability shield even when the risk of cross-contact is negligible based on their actual facility practices.

This inconsistency has a documented negative effect on consumers with food allergies. Research published in journals including the Journal of Allergy and Clinical Immunology has found that many allergy sufferers simply ignore advisory statements because they appear on so many products — including products where actual cross-contact risk is extremely low. When your voluntary warning is indistinguishable from a blanket disclaimer, it stops functioning as a genuine safety communication tool. For food businesses, this is not just an ethical issue; it affects whether allergy-aware customers trust your brand enough to purchase from you.

From a legal standpoint, voluntary advisory statements do provide some protection against liability claims where a manufacturer can demonstrate that the warning was genuine and based on a real risk assessment. However, they do not provide unlimited protection. If your facility has documented cross-contact risks and you fail to include any advisory statement, and a customer suffers an allergic reaction, the absence of a warning will likely be held against you in any legal action. Conversely, if you include an advisory statement on a product where no credible cross-contact risk exists, you may face consumer fraud allegations.

Recommended Language and What to Avoid

When a voluntary advisory statement is warranted based on your facility risk assessment, the most widely recognised and least ambiguous phrasing is "May contain [allergen]." This phrasing is short, direct, and widely understood by consumers, food retailers, and regulatory bodies. Alternatives like produced in a facility that also processes are longer and less immediately understood, particularly for online product listings where customers are skimming quickly. "Made on shared equipment with [allergen]" is appropriate where cross-contact risk is specifically tied to equipment sharing rather than general facility proximity.

Phrases to avoid include vague language like "this product may come into contact with various allergens" or umbrella statements that list six or seven allergens with no differentiation. These catch-all disclaimers lack credibility and do not give allergy sufferers the specific information they need to make an informed decision. The FDA has indicated in public communications that it views poorly targeted advisory statements as potentially misleading, and food retailers like major grocers and specialty food platforms increasingly push back on suppliers whose labeling lacks specificity.

For your Shopify product pages, your advisory statement should mirror exactly what appears on your physical packaging. Do not add additional allergens to your online listing that are not on your label, and do not omit advisory statements from your digital listing that appear on the physical product. Consistency across packaging and digital channels is both a consumer safety imperative and a legal best practice. Tools like Allergen Matrix are designed to help Shopify merchants manage this consistency across large product catalogs without manual errors.

Practical Steps for Shopify Food Sellers

Implementing voluntary allergen warnings correctly starts with documentation, not copywriting. Before you write a single word on your product page, you need a current allergen risk assessment for every product you sell. This means reviewing ingredient specification sheets from every supplier, understanding your own production environment if you manufacture, and asking your co-manufacturer or third-party producer to provide their allergen management procedures in writing. A supplier who cannot provide this documentation should be treated as a risk factor.

Once you have your risk assessments, create an allergen matrix for your product range — a simple spreadsheet listing every product, every mandatory allergen ingredient, and every cross-contact risk identified through your assessment. This document becomes the single source of truth for your label copy, your online listings, and any future reformulations. If you are selling more than ten to fifteen SKUs, managing this manually in a spreadsheet quickly becomes error-prone, particularly when ingredients change or when you add products to your range.

On Shopify specifically, ensure that allergen information appears in a consistent location on every product page — ideally in a dedicated section below the main product description, not buried inside long blocks of marketing copy. Customers with food allergies are looking for this information deliberately and quickly, and if they cannot find it, they will leave your store rather than risk their health. Clear, well-structured allergen information also reduces customer service queries and return requests, which directly impacts your operational efficiency.

Conclusion

Voluntary allergen warnings in the US occupy a unique and often misunderstood space in food labeling law. FALCPA mandates declarations for intentional allergen ingredients, but cross-contact risks remain the responsibility of individual manufacturers to communicate — or not — through advisory statements. The key takeaways are straightforward: base any "may contain" statement on a genuine risk assessment, use specific and clear language, ensure total consistency between your physical labels and your Shopify product listings, and never use advisory statements as a generic liability blanket.

For food businesses scaling on Shopify, getting allergen management right is not just a compliance exercise — it is a trust-building exercise with a customer segment that has very long memories and very high standards. Start with your documentation, build your allergen matrix, and audit your product pages against your physical labels today.

Try Allergen Matrix free at saltai.app — no credit card required.