FDA Acetal for Food and Medical Applications (2026)

Q: Is acetal (Delrin / POM) food safe?

Natural (white/ivory) acetal homopolymer and copolymer are compliant with FDA 21 CFR 177.2470 for food contact applications. This regulation covers polyacetal resins in contact with food. The key qualification: only natural-color grades are reliably FDA-compliant. Black and colored acetal grades use pigments and additives that may not be compliant — always verify the specific grade with the material supplier and request a compliance certificate for regulated applications.

Q: What FDA regulation covers acetal for food contact?

FDA 21 CFR 177.2470 — Polyacetal resins — is the applicable regulation. It permits acetal homopolymer and copolymer resins for food contact applications subject to specified extractable limits — the maximum amount of substances the resin can release into food under test conditions. The regulation requires the resin to meet specified purity standards and not impart substances to food above permitted thresholds. Natural acetal rod and plate stock from major producers (Celanese Delrin, BASF Ultraform) is typically produced to comply with this standard.

Q: Can acetal be autoclaved for medical sterilization?

No. Standard acetal (POM) cannot withstand autoclave sterilization at 121–134°C. Autoclave temperatures exceed acetal's continuous service temperature (90–100°C), causing creep, deformation, and dimensional change in precision features. For parts requiring autoclave sterilization, PEEK is the standard alternative. Acetal can be sterilized with ethylene oxide (EtO) at temperatures below 60°C, or with cold chemical disinfectants, without dimensional compromise.

Q: What does USP Class VI mean for acetal?

USP Class VI (United States Pharmacopeia Biological Test Class VI) is a biocompatibility testing standard that evaluates materials for systemic injection, intracutaneous injection, and implantation toxicity. Acetal grades tested and certified to USP Class VI have passed these biological safety tests. USP Class VI acetal is required for medical devices that contact bodily fluids. Not all acetal grades are tested — verify the specific grade has a USP Class VI certificate from the manufacturer.

Q: Is black acetal food safe?

Not reliably. Black acetal typically uses carbon black pigment, which may introduce substances not compliant with FDA 21 CFR 177.2470 food contact regulations. Some black acetal grades are formulated with FDA-compliant black pigments — but this must be verified with a specific compliance letter from the material supplier. For any food-contact application, natural (white/ivory) acetal is the safe default unless a specific FDA-compliant black grade certificate is in hand.

Important Disclaimer: This Is Educational Content, Not Legal or Regulatory Advice.

If your application requires FDA or medical compliance, do not rely on this guide as your sole verification — always confirm with your quality and regulatory teams. FDA compliance for food-contact and medical materials requires verification against specific regulations, grade data sheets, and — for regulated medical devices — FDA submissions or notified body review. This guide explains how acetal fits into common compliance frameworks. Always verify with your material supplier, quality team, and regulatory affairs before using any material in a regulated application.

Section 1 of 5

FDA 21 CFR 177.2470: The Governing Regulation

If your acetal part contacts food during processing, this is the regulation you need to satisfy — and the one your customer's QA team will reference. FDA 21 CFR Part 177 governs indirect food additives — materials that contact food during processing, storage, or packaging but aren't intentionally added to it. Subpart 177.2470 covers polyacetal resins specifically.

What 21 CFR 177.2470 Covers

Permits acetal homopolymer (POM-H) and copolymer (POM-C) resins for use in contact with food
Specifies base resin and allowable additive types and amounts
Covers all food types and contact conditions up to 121°C (250°F)
Applies to finished parts machined from compliant resin stock
Does not distinguish between POM-H and POM-C — both compliant when base resin meets spec

What 21 CFR 177.2470 Does NOT Cover

Pigments and colorants added to the base resin — colors other than natural require separate verification
Non-compliant additives (e.g., some lubricants or stabilizers used in non-food grades)
Parts that contact food at temperatures above 120°C — POM degrades near its melt point
Parts requiring direct human body implantation — different regulatory pathway required
Specific lot or batch compliance — requires certificate of conformance from material supplier

Section 2 of 5

Color and Grade Selection for Food/Medical

When you specify acetal color on a food-contact drawing, that choice directly determines whether your part passes or fails a compliance audit. Color is not cosmetic in regulated applications — it determines which grades are compliant.

Color / Grade	FDA 21 CFR 177.2470	USP Class VI (select)	Notes
Natural / white (unfilled POM-H)	Compliant — standard grade	Available in certified lots	Default for all food and medical contact applications
Natural / ivory (unfilled POM-C)	Compliant — standard grade	Available in certified lots	Same compliance as POM-H natural; use POM-C for thick sections
Black (standard carbon black)	Not reliably compliant	Not typically certified	Standard black uses non-food-grade carbon black — avoid for food contact
Black (FDA-compliant grade)	Compliant if certified	Available (verify)	Specifically formulated with FDA-permitted black pigment — requires compliance cert from supplier
PTFE-filled natural (AF grade)	Verify with supplier	Check specific grade	PTFE filler is generally inert — but verify the specific AF grade meets 21 CFR 177.2470
Glass-filled acetal	Generally not compliant	Not typically certified	Glass fiber grades typically not formulated for food contact; use unfilled for food applications
Colored (blue, red, etc.)	Verify each colorant	Rarely available	Require colorant-by-colorant compliance verification — not practical for most applications

Section 3 of 5

Relevant Standards and Certifications

Multiple standards may apply depending on whether your application is food processing, medical device, or pharmaceutical.

FDA 21 CFR 177.2470

Food Contact — USA

Governs acetal resins for indirect food contact. Permits POM-H and POM-C in natural grades for all food types. Require supplier compliance certificate stating specific material lot meets 21 CFR 177.2470.

Typical applications: Food processing equipment, beverage dispensing, conveyor components, food packaging machinery

EU Regulation 10/2011

Food Contact — Europe

EU equivalent to FDA 21 CFR for plastic materials in food contact. POM is listed as permitted polymer. Requires overall migration test results and specific migration limits for listed monomers/additives.

Typical applications: Food contact products sold in European markets

USP Class VI

Biocompatibility — Medical

US Pharmacopeia biological testing protocol evaluating systemic, intracutaneous, and implantation toxicity. Acetal grades certified to USP Class VI have passed these in vivo tests. Required for many medical device components contacting bodily fluids or tissues.

Typical applications: Medical devices, fluid handling components, diagnostic equipment housings

ISO 10993

Biocompatibility — Medical Devices

International standard series for biological evaluation of medical devices. More comprehensive than USP Class VI. Specific tests depend on device classification and intended use (duration and type of body contact). Acetal can be evaluated under ISO 10993 with appropriate testing program.

Typical applications: Regulated medical devices requiring 510(k) or CE mark

FDA-Grade Acetal Parts — Natural Color, Verified Grade

MakerStage machines natural-color acetal (POM-H and POM-C) for food processing and medical device applications. Upload your CAD file and specify your compliance requirements — free DFM review on every order.

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Section 4 of 5

Sterilization Compatibility

If your acetal part requires sterilization, choosing the wrong method will warp precision features and scrap the part. Sterilization method selection is critical — the wrong method destroys precision acetal parts.

Sterilization Method	Temperature	Acetal Compatibility	Notes
Steam autoclave (121°C, 15 psi)	121°C (250°F)	✗ Not compatible	Exceeds continuous service temp; causes creep, deformation, loss of tight tolerances
Steam autoclave (134°C)	134°C (273°F)	✗ Not compatible	Severe degradation — POM melts and deforms; use PEEK for autoclavable parts
Ethylene oxide (EtO)	37–60°C	✓ Compatible	Standard sterilization for acetal medical components; no dimensional impact at these temperatures
Radiation (gamma, e-beam)	Room temperature	⚠ With caution	High-dose gamma (> 25 kGy) can cause chain scission and embrittlement in POM; verify with specific dose and grade
Chemical disinfection (IPA, glutaraldehyde)	Room temperature	✓ Compatible (most)	Verify against acetal chemical resistance chart — avoid bleach and strong oxidizers
Dry heat sterilization (160°C)	160°C	✗ Not compatible	Far above POM service temperature; severe degradation
UV disinfection	Room temperature	✓ Compatible	UV does not affect material properties at room temperature; ensures surface disinfection only

Section 5 of 5

Design Rules for Food and Medical Acetal Parts

Your part geometry matters as much as your material choice — blind holes, sharp corners, and poor drainage create contamination traps that fail sanitary inspections. Physical design affects cleanability and contamination risk as much as material selection.

Cleanability Design

No blind bores or blind pockets where food particles can accumulate
Minimum radii 1/16 in. (1.6 mm) on all internal corners — no sharp internal corners
Avoid horizontal facing flat surfaces that collect standing water
Drainage: ensure all surfaces drain fully; avoid pools at joints
Avoid threaded blind holes in food zones — threading is a contamination trap

Surface Finish

Food contact surfaces: Ra 32–63 µin (0.8–1.6 µm) as-machined
Smoother finishes (Ra < 32 µin (< 0.8 µm)) do not provide additional safety benefit and increase cost
No painted, coated, or plated surfaces in food contact zones — coatings can chip
Engrave part number / lot traceability on non-food-contact surface only
Anodize and conversion coatings not applicable to acetal

Material Specification

Drawing callout: "Acetal Homopolymer (POM-H) per ASTM D6778, natural color, FDA 21 CFR 177.2470 compliant"
Request material compliance certificate (CoC) from machine shop supplier
Request heat/lot traceability if required by your QMS
Specify "Natural color only" explicitly — prevent accidental substitution with colored or filled grade

Assembly and Fasteners

Fasteners in food zones: 316L stainless steel only
Thread-locking compounds (Loctite, etc.) in food zones: FDA-grade formulations only
No aluminum fasteners — aluminum corrodes and can contaminate food streams
Brass bushings or inserts: not for food contact zones — copper content not FDA-listed

Procurement Checklist: What to Request from Your Supplier

If you're sourcing FDA-grade acetal parts, include these line items on your PO or RFQ to avoid compliance gaps at incoming inspection.

1Material certificate of conformance (CoC) citing FDA 21 CFR 177.2470 compliance for the specific resin lot used
2Material test report (MTR) or mill cert with resin grade, lot number, and manufacturer
3Specify "Natural color (white/ivory) acetal only" on the PO — prevent substitution with pigmented grades
4If USP Class VI is required: request copy of biocompatibility test report from resin manufacturer (not the machine shop)
5Drawing callout: "Acetal Homopolymer (POM-H) per ASTM D6778, natural color, FDA 21 CFR 177.2470 compliant"
6Lot traceability requirement: supplier must record which resin lot was used for each production run
7If black acetal is required: request supplier-specific FDA compliance letter for the exact black grade — do not assume compliance

Frequently Asked Questions

Is acetal (Delrin / POM) food safe?

Natural (white/ivory) acetal homopolymer and copolymer are compliant with FDA 21 CFR 177.2470 for food contact applications. This regulation covers polyacetal resins in contact with food. The key qualification: only natural-color grades are reliably FDA-compliant. Black and colored acetal grades use pigments and additives that may not be compliant — always verify the specific grade with the material supplier and request a compliance certificate for regulated applications.

What FDA regulation covers acetal for food contact?

FDA 21 CFR 177.2470 — Polyacetal resins — is the applicable regulation. It permits acetal homopolymer and copolymer resins for food contact applications subject to specified extractable limits — the maximum amount of substances the resin can release into food under test conditions. The regulation requires the resin to meet specified purity standards and not impart substances to food above permitted thresholds. Natural acetal rod and plate stock from major producers (Celanese Delrin, BASF Ultraform) is typically produced to comply with this standard.

Can acetal be autoclaved for medical sterilization?

No. Standard acetal (POM) cannot withstand autoclave sterilization at 121–134°C. Autoclave temperatures exceed acetal's continuous service temperature (90–100°C), causing creep, deformation, and dimensional change in precision features. For parts requiring autoclave sterilization, PEEK is the standard alternative. Acetal can be sterilized with ethylene oxide (EtO) at temperatures below 60°C, or with cold chemical disinfectants, without dimensional compromise.

What does USP Class VI mean for acetal?

USP Class VI (United States Pharmacopeia Biological Test Class VI) is a biocompatibility testing standard that evaluates materials for systemic injection, intracutaneous injection, and implantation toxicity. Acetal grades tested and certified to USP Class VI have passed these biological safety tests. USP Class VI acetal is required for medical devices that contact bodily fluids. Not all acetal grades are tested — verify the specific grade has a USP Class VI certificate from the manufacturer.

Is black acetal food safe?

Not reliably. Black acetal typically uses carbon black pigment, which may introduce substances not compliant with FDA 21 CFR 177.2470 food contact regulations. Some black acetal grades are formulated with FDA-compliant black pigments — but this must be verified with a specific compliance letter from the material supplier. For any food-contact application, natural (white/ivory) acetal is the safe default unless a specific FDA-compliant black grade certificate is in hand.

Related Resources

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FDA-Grade Acetal Parts with Material Traceability

CNC machining in natural-color acetal (POM-H, POM-C) for food processing and medical device applications. Material certificates available. Free DFM review on every order.

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FDA-Grade Acetal for Food and Medical Applications