21 CFR 177.1520: Olefin Polymer Limits and Use Conditions

21 CFR 177.1520 is the federal regulation that determines whether polypropylene and other olefin polymers can lawfully touch food in the United States. It fixes what the polymer must be made of, how much of it can migrate into food during extraction testing, and which temperature-and-time conditions of use the finished article is cleared for. Meet its specifications and your material is a permitted indirect food additive. Miss them and any food packaged in it is adulterated by operation of law.

Which Materials the Rule Covers

Section 177.1520 sits inside 21 CFR Part 177, which governs polymers used as indirect food additives — substances that can become a component of food through contact with packaging or equipment rather than being added to it.¹ Under 21 U.S.C. 348, any food additive is treated as unsafe unless it conforms to a prescribing regulation or is covered by an effective Food Contact Notification.² For olefin polymers, 177.1520 is that prescribing regulation.

The rule covers a family, not a single resin. Polypropylene homopolymer made by catalytic polymerization of propylene is the most familiar, but polyethylene, olefin copolymers combining monomers such as ethylene and propylene, and polymethylpentene are all in scope.³ Each polymer type has its own numerical thresholds; a value that clears polyethylene does not automatically clear polypropylene.

Composition and Extractable Limits

Paragraph (c) of the regulation sets the pass/fail numbers the base polymer has to hit before anything is fabricated from it. For polypropylene homopolymer, the specifications are:³

Density between 0.880 and 0.913 g/cm³
Melting point between 160°C and 180°C
Maximum n-hexane extractable fraction of 6.4% by weight at reflux temperature
Maximum xylene-soluble fraction of 9.8% by weight at 25°C

The n-hexane number caps low molecular weight material that could migrate out of the polymer. The xylene number reflects the polymer’s crystallinity and molecular weight distribution; a higher soluble fraction points to more amorphous, lower-weight material that is more likely to leach. Testing is performed on the basic polymer in film form not exceeding 4 mils (0.102 mm) in thickness.³

Copolymers and other olefin polymers listed in the regulation have their own thresholds in paragraph (c). Read the paragraph item that matches the exact polymer you are qualifying, not the polypropylene numbers by default.

Conditions of Use and the Thickness Rule

Passing composition specs is not a license to use the material with any food at any temperature. Section 177.1520 cross-references Table 2 of 21 CFR 176.170, which sorts food contact scenarios into eight conditions of use based on thermal severity:⁴

Condition A: high-temperature heat sterilization above 212°F
Condition B: boiling water sterilization at 212°F for 30 minutes
Condition C: hot-filled or pasteurized above 150°F
Condition D: hot-filled or pasteurized below 150°F
Condition E: room temperature fill and storage, no thermal treatment
Condition F: refrigerated storage, no thermal treatment
Condition G: frozen storage, no thermal treatment
Condition H: frozen or refrigerated foods reheated in the container before serving

A is the harshest, G the mildest, and H is a hybrid for ready-prepared meals reheated in their packaging. Extraction testing for each condition uses food-simulating solvents — distilled water, 8% or 50% ethanol, and n-heptane — at time-and-temperature combinations meant to mirror real service.⁴

Thickness is the other gate. Polypropylene articles at or below 0.102 mm (0.004 inches, or 4 mils) can qualify for all eight conditions, A through H. Thicker articles are limited to conditions C through G, which excludes the harshest sterilization scenarios and the reheat-in-container use.³ Thinner material means less polymer mass per unit of food-contact surface, and less total extractable available to migrate.

The practical trap sits here. A resin can pass every paragraph (c) test in the lab and still fail compliance if the finished article is sold into a use more severe than what was validated. A container tested at Condition E does not cover a hot-fill application above 150°F, no matter how comfortably it cleared the composition specs. The test conditions have to equal or exceed the actual conditions of use.

Additives, Adjuvants, and Colorants

A polypropylene resin almost never reaches a food contact application as pure polymer. Antioxidants, stabilizers, processing aids, and colorants are compounded in to make the finished product perform. Section 177.1520(b) allows these optional adjuvant substances, but only from defined sources:³

Substances permitted by regulations in 21 CFR Parts 170 through 189
Substances generally recognized as safe (GRAS) for food and food packaging
Substances with a prior sanction or approval
Substances specifically listed in the adjuvant table within 177.1520(b) itself

That adjuvant table is long and detailed, with entries ranging from hydrogenated petroleum resins to specific catalyst deactivators. Many entries carry their own limits: certain polymer types only, maximum concentrations, or specified conditions of use. Clearance is not portable across the table. An adjuvant approved for polyethylene under Conditions E through G is not automatically cleared for polypropylene under Condition A.

Colorants have to comply with 21 CFR 178.3297, which governs colorants for polymers.³ Color additives also have to meet the listing requirements in 21 CFR Part 73; titanium dioxide, for instance, cannot exceed 1% by weight of food when used as a colorant.⁵ Whatever the formulation includes, the finished polymer still has to meet every specification in paragraph (c).

Statements of Compliance and Records

Nothing in 177.1520 dictates a specific recordkeeping format, but demonstrating compliance without documentation is not realistic. Three record types carry most of the weight in a typical supply chain:

Certificates of Analysis showing the resin meets the density, melting point, n-hexane extractable, and xylene-soluble limits in paragraph (c).
Extraction test reports for the finished article under the applicable conditions of use, identifying the food simulants and time-temperature combinations used.
Adjuvant clearance records confirming every additive, stabilizer, and colorant is cleared under an applicable FDA regulation, is GRAS, or holds prior sanction.

The customary industry document tying these together is a Statement of Compliance issued by the resin supplier or converter. A useful SOC names the specific polymer type, the paragraph (c) item it satisfies, and the conditions of use it was validated for. A statement that only says “FDA compliant” without naming conditions of use is worth pushing back on before you specify the material.

For operations subject to Current Good Manufacturing Practice under 21 CFR Part 117, food safety records must be retained for at least two years after the date they were prepared, and records supporting the general adequacy of equipment or processes must be kept for at least two years after their use is discontinued.⁶ Even outside Part 117’s scope, that retention window is a reasonable floor.

When 177.1520 Is Not Enough

Two situations sit outside the regulation and need their own path.

The first is a new food contact substance not already covered by 177.1520 or another prescribing regulation. The route is a Food Contact Notification submitted to the FDA. The agency has 120 days to review; if it does not object in that window, the substance can be marketed.⁷ An effective FCN covers only the specific substance reviewed and only the manufacturer or supplier named in it, so a competitor cannot piggyback on someone else’s notification. If your polypropylene uses only monomers, adjuvants, and colorants already cleared under 177.1520 and its cross-referenced regulations, no FCN is needed.

The second is post-consumer recycled polypropylene. Compliance of the virgin resin does not carry over to recycled material, which may have picked up contamination during its previous use or during recycling. The FDA reviews recycled plastics case by case. A manufacturer submits the recycling process to the Office of Food Additive Safety with source controls, evidence that the process removes incidental contaminants, and the intended conditions of use. Without strict source control, the submitter must show through surrogate contaminant testing that no contaminant migrates into food above 0.5 parts per billion — the dietary concentration FDA considers negligible.⁸ If the process is acceptable, the FDA issues a No Objection Letter, and a sublicensee running the same process for the same use does not need a separate letter.⁹

Consequences of Non-Compliance

Non-compliant food contact material has legal teeth. Under 21 U.S.C. 342, food is adulterated if its container is composed in whole or in part of any substance that may render the contents injurious to health.¹⁰ A food additive, including a food contact substance, is deemed unsafe unless it conforms to a prescribing regulation like 177.1520 or is covered by an effective FCN.² Food containing an unsafe food additive is adulterated by definition.

The FDA’s enforcement options include injunctions ordering the violating activity to stop, criminal prosecution for prohibited acts under the Food, Drug, and Cosmetic Act, and seizure of adulterated products in interstate commerce through a Complaint for Forfeiture in federal court. Imports that fail to comply can be refused admission at the border. The exposure follows the product: it lands on the packaging manufacturer, on the converter, and on anyone in the chain who introduces adulterated food into commerce.

1
eCFR. 21 CFR Part 177 – Indirect Food Additives: Polymers
2
Office of the Law Revision Counsel. 21 USC 348 – Food Additives
3
eCFR. 21 CFR 177.1520 – Olefin Polymers
4
eCFR. 21 CFR 176.170 – Components of Paper and Paperboard in Contact With Aqueous and Fatty Foods
5
eCFR. Listing of Color Additives Exempt From Certification
6
eCFR. 21 CFR Part 117 Subpart F – Requirements Applying to Records That Must Be Established and Maintained
7
U.S. Food and Drug Administration. About the FCS Review Program
8
U.S. Food and Drug Administration. Recycled Plastics in Food Packaging
9
U.S. Food & Drug Administration. Submissions on Post-Consumer Recycled (PCR) Plastics for Food-Contact Articles
10
Office of the Law Revision Counsel. 21 USC 342 – Adulterated Food