FDA 21 CFR Regulations for Food-Contact Desiccants

What Is FDA 21 CFR and Why Does It Apply to Desiccants?

Title 21 of the Code of Federal Regulations (21 CFR) is the federal regulatory framework administered by the US Food and Drug Administration (FDA), governing the manufacturing and distribution of food, drugs, and cosmetics in the American market. The foundational legal authority is the Federal Food, Drug, and Cosmetic Act (FDCA), with Section 409 addressing food additives and Section 201(s) defining "food contact substance."

A desiccant sachet is classified as a "food contact substance" when it is placed inside sealed packaging together with food — for example, inside a box of cookies, a jar of dried herbs, or a bag of dried seafood. In these cases, both the active ingredient (silica gel, clay) and the sachet packaging material (Tyvek, nonwoven, OPP) must have a valid regulatory basis under 21 CFR.

FDA classifies food-related substances into three main categories:

• GRAS (Generally Recognized As Safe) — 21 CFR Parts 182-186. Substances with a long history of safe use or scientific consensus; no pre-market approval required.
• Prior-sanctioned substances — 21 CFR Part 181. Substances approved before FDCA 1958 took effect.
• Food additives (petition-based) — 21 CFR Parts 170-180. New substances require a Food Additive Petition and formal FDA approval.

For more guidance on selecting the right desiccant for US-bound food shipments, see our article on food-contact desiccants — FDA standard for US export.

21 CFR §184.1711 — Silicon Dioxide GRAS Status

21 CFR §184.1711 is the central provision for any silica gel desiccant manufacturer targeting the US market. Key points include:

• Recognized substance: Silicon dioxide (SiO₂) — including amorphous silica gel and fumed silica.
• Usage limit: Maximum 2% by weight of dry food when used as an anticaking agent. For desiccant sachets placed outside food within sealed packaging, there is no absolute quantity limit, but migration into food must be negligible.
• GRAS basis: Established through long history of use and scientific evidence. FDA does not require pre-approval for silica gel when used in accordance with intended conditions.

GRAS status does not mean "no documentation required." On the contrary, to satisfy requirements from US buyers and customs authorities, desiccant manufacturers must maintain:

1. Certificate of Analysis (CoA) — confirming SiO₂ content ≥ 99%, absence of cobalt chloride, and no unapproved indicators.
2. Specification Sheet — detailing raw materials, manufacturing process, and storage conditions.
3. Letter of Guarantee — affirming compliance with 21 CFR §184.1711 and all applicable FDA regulations.

Common food products using enclosed silica gel desiccants: dried seafood, dried herbs, dietary supplement capsules, cashew nuts, and exported coffee beans. In all these cases, the desiccant sachet does not directly contact the food — it absorbs moisture from the air inside the sealed packaging.

Official reference: 21 CFR §184.1711 — eCFR.gov.

See also: Silica gel MSDS GHS — safety data sheet covering silica gel composition.

21 CFR Parts 174-186 — Indirect Food Additives for Packaging

21 CFR Parts 174-186 regulate indirect food additives — substances not intentionally added to food but which may migrate from packaging materials into food during storage, transport, or processing. For desiccant sachets, the packaging materials must be evaluated within this regulatory framework.

• 21 CFR Part 176 — Paper and paperboard components: Tyvek (HDPE flash-spun nonwoven) and kraft paper used as desiccant sachet material may fall under this part if they have paper-based components. Bleaching agents, coatings, and adhesives must appear on the approved substances list.
• 21 CFR Part 177 — Polymers: Polypropylene nonwoven (OPP), PET laminated film, and polyethylene used as sachet material must be approved polymers with appropriate conditions of use. For example, PET is listed under §177.1630 with multiple conditions depending on food contact temperature.
• 21 CFR Part 175 — Adhesives and coating components: Adhesives used in heat-sealing desiccant sachets must comply with adhesive regulations.
• 21 CFR Part 178 — Adjuvants, production aids, sanitizers: Includes antistatic agents and lubricants used in packaging manufacturing.

Vietnamese desiccant manufacturers must request a Statement of Compliance from their packaging material suppliers (Tyvek, nonwoven, OPP), specifying which 21 CFR parts apply. The desiccant manufacturer then consolidates this information into the Letter of Guarantee issued to the food exporter.

Official reference: FDA Food-Contact Substances — FDA.gov.

For the EU equivalent: EC 1935/2004 — EU equivalent regulation.

Letter of Guarantee vs. Declaration of Compliance

Criterion	Letter of Guarantee (LoG)	Declaration of Compliance (DoC)
Nature	Commercial commitment — supplier guarantees product compliance with applicable regulations	Technical document — lists specific regulations, conditions of use, and test data where applicable
Signatory	Authorized representative of manufacturer/supplier	Technical or regulatory lead (QA Manager, Regulatory Affairs)
Minimum content	Product name, lot number, applicable regulation (21 CFR §184.1711), confirmation of no prohibited substances	Substance list, CAS numbers, permitted limits, migration data if required, conditions of use
FDA requirement	Not mandatory by regulation, but commonly required by US buyers	Mandatory for certain food contact substances under the Food Contact Notification (FCN) program
Frequency	Per shipment or per contract	Per product/formulation — updated when composition changes

CEMACO Sai Gon provides a standard Letter of Guarantee for all non-indicator silica gel and clay desiccant products, referencing 21 CFR §184.1711 and confirming the absence of CoCl₂. Download: Letter of Guarantee + Silica Gel MSDS 2025.

See also: CEMACO Sai Gon ISO 9001 + HACCP Certifications — the quality management foundation.

Related: HACCP for food-contact desiccants.

Common Mistake — Blue CoCl₂ Silica Gel Is NOT FDA-Approved

This is the most serious and most common mistake in the industry: using cobalt chloride (CoCl₂) indicating blue silica gel in food packaging destined for the US or EU markets.

• FDA has not approved CoCl₂ for food contact under any provision of 21 CFR. There is no GRAS affirmation and no approved food additive petition for CoCl₂ in food-contact applications.
• REACH SVHC (EU): Cobalt dichloride is listed as a Substance of Very High Concern (SVHC) under REACH Regulation (EC) No 1907/2006. Products exported to the EU containing SVHC above 0.1% (w/w) require declaration and may be refused entry.
• Legal risk: If a food shipment is found to contain blue CoCl₂ silica gel at a US port, FDA may issue an Import Alert, resulting in the entire shipment being detained or destroyed at significant cost.
• Safe alternatives: White (non-indicating) silica gel or blue/pink silica gel using organic indicators free of cobalt — confirmed by CoA and Letter of Guarantee from the manufacturer.

CEMACO Sai Gon exclusively uses non-indicating (white) silica gel and FDA-compliant Tyvek/nonwoven materials across the entire food-contact product range.

Browse our full range: CEMACO Sai Gon silica gel products — complete catalog with technical specifications.

Application guide: Desiccant applications in the food industry.

Frequently Asked Questions

What is GRAS and why does it matter for silica gel desiccants?

GRAS (Generally Recognized As Safe) is a legal status granted by the US FDA allowing the use of a substance in food without prior approval. Silica gel (SiO₂) holds GRAS status under 21 CFR §184.1711, meaning companies can legally use silica gel in food packaging without filing a Food Additive Petition — provided use conditions are followed.

Who in Vietnam must comply with 21 CFR §184.1711?

(1) Vietnamese food manufacturers exporting to the US who use desiccant sachets inside food packaging; (2) desiccant manufacturers or importers supplying to US exporters. The desiccant supplier must issue a Letter of Guarantee; the food exporter is responsible for verifying and retaining the document for FDA inspection.

What is the difference between a Letter of Guarantee and a Declaration of Compliance?

A Letter of Guarantee is a concise commercial commitment signed by the supplier confirming compliance with applicable FDA regulations. A Declaration of Compliance is more detailed, listing specific regulations, substances, conditions of use, and supporting technical data. For silica gel desiccants exported to the US, a Letter of Guarantee is generally sufficient for buyer requirements; a full DoC is used for audits or FDA registration purposes.

Is blue CoCl₂ silica gel approved by FDA for food contact?

No. Cobalt chloride (CoCl₂) has no GRAS affirmation and no approved Food Additive Petition for food-contact applications under 21 CFR. Using blue CoCl₂ silica gel in food packaging for US export violates 21 CFR and may result in an Import Alert, shipment detention, or destruction at port.

Where can I download CEMACO Sai Gon's Letter of Guarantee?

Visit our technical documents page to download the Letter of Guarantee and Silica Gel MSDS (2025 edition). For shipment-specific documentation, contact our hotline at 0983 929 232 or submit a quotation request.

Read more — flagship article: Desiccant MSDS Handbook — Safety Documentation for US, EU & Japan Export Markets — CEMACO's FDA Letter of Guarantee + EC 1935/2004 DoC workflow and the 5 most common customs MSDS errors for US food shipments.