The little triangle stamped on a plastic container tells you what resin it’s made from — but it does not, by itself, tell you whether that container is legal to put food in. That distinction trips up a lot of packaging and compliance teams, especially when a supplier says “it’s a #5, so it’s food-safe” as if the number were a certification.
This guide breaks down what each resin identification code (RIC) actually means, which resins are commonly used for food contact, and what a compliance manager needs to verify beyond the number itself before signing off on a packaging spec.
Quick Answer
Resins #2 (HDPE), #4 (LDPE), and #5 (PP) are the most widely used and trusted for food-contact packaging, and #1 (PET/PETE) is also commonly used for food and beverage containers, especially single-use ones. Resin #3 (PVC) and #6 (PS) are used in some food applications but carry more scrutiny and are increasingly avoided. #7 (“Other”) is a catch-all category that can include polycarbonate and other resins, so it needs case-by-case verification rather than a blanket answer.
The 7 Resin Codes, and What They Mean for Food Contact
#1 – PET/PETE (polyethylene terephthalate): The clear plastic used in most bottled beverages and many clamshell food containers. It’s approved for food contact and widely recycled, but it’s generally designed for single use — reused or heavily scratched PET containers are more likely to harbor bacteria or degrade, which is a food-safety issue separate from the resin’s initial approval.
#2 – HDPE (high-density polyethylene): The opaque plastic used for milk jugs, some food tubs, and many bottles. It’s one of the most broadly accepted resins for food storage and doesn’t have significant known leaching concerns under normal use.
#3 – PVC (polyvinyl chloride): Used for some cling films and rigid packaging. Rigid PVC formulations can be compliant for food contact, but PVC as a category is under more regulatory and consumer scrutiny due to plasticizers and additives used in flexible versions, and it’s rarely accepted by curbside recycling programs.
#4 – LDPE (low-density polyethylene): Found in bread bags, squeeze bottles, and some film packaging. Like HDPE, it’s considered one of the safer, more stable resins for food contact.
#5 – PP (polypropylene): The resin behind yogurt cups, deli containers, and many microwave-safe tubs. It has good heat resistance and is a standard choice for food packaging that needs to survive reheating.
#6 – PS (polystyrene): Covers both rigid plastic (cutlery, some cups) and foamed polystyrene (egg cartons, some takeout containers, packing foam). Polystyrene has drawn increasing regulatory and retailer pushback, and several states and cities restrict foam food-service packaging specifically — so a #6 spec needs a jurisdiction check, not just an FDA check.
#7 – Other: A catch-all for resins that don’t fit categories 1–6, including polycarbonate, certain nylons, and multi-layer or composite materials. Because this bucket is so broad, a #7 mark tells you almost nothing about food safety on its own — you need to know the actual polymer and its food-contact clearance before using it.
The Resin Code Isn’t a Food-Safety Certification
The resin identification code system (standardized under ASTM D7611) exists to help sorters and recyclers identify plastic types — it was never designed as a food-safety label, and the FDA doesn’t administer or endorse it. Two containers stamped with the same number can have different additives, colorants, and manufacturing processes, and only some of those formulations will meet food-contact requirements.
Actual food-contact clearance in the US comes from FDA regulations under 21 CFR Parts 174–178, which list specific substances and conditions of use approved for contact with food, or from a Food Contact Notification (FCN) that the FDA has accepted for a specific manufacturer and use. When you’re vetting a supplier or packaging spec, the resin number is a starting point for narrowing down material family — the real documentation to request is the supplier’s statement of food-contact compliance, migration testing data, or reference to the applicable FDA regulation or FCN number covering that exact formulation.
Recycled-content packaging, including recycled PET, follows its own path. The FD&C Act and FDA’s implementing regulations don’t require special premarket clearance for recycled plastic — the legal standard (21 CFR 174.5) is that the material be “of a purity suitable for its intended use,” the same bar virgin resin has to clear, and manufacturers are responsible for demonstrating that using sound science. For PET and PEN specifically, FDA has gone a step further on chemical (“tertiary”) recycling: because methanolysis and glycolysis break the polymer down to monomers or oligomers that are readily purified before being repolymerized, FDA has concluded that these tertiary processes inherently produce material pure enough for food contact — so the agency no longer evaluates individual tertiary PET/PEN recycling processes or issues opinion letters for them at all. Mechanical recycling is treated differently: a mechanical recycler can still ask FDA for an informal, voluntary review of its process and, if FDA has no concerns, receive a letter of no objection (LNO) to show customers as added assurance. That LNO pathway is a useful credential to ask a mechanical recycler for, but it has never been a legal requirement — and for tertiary PET/PEN recycling, there’s no individual FDA letter to ask for in the first place, so don’t treat its absence as a red flag.
Tips / Common Mistakes
Don’t treat the RIC number as a pass/fail food-safety test — it identifies resin family, not formulation or compliance status. Always ask suppliers for the specific food-contact clearance (FDA regulation citation or FCN) tied to their exact material, not just the general reputation of the resin.
Watch #7 closely. Because it’s a catch-all, packaging teams sometimes assume it’s automatically non-compliant or automatically fine — neither is safe to assume without checking the actual polymer.
Factor in end use, not just material. A #5 PP tub rated for cold storage may not have been tested or cleared for microwave reheating at the temperatures your product requires — heat and migration testing are use-specific.
Track state and local rules separately from FDA rules. Several jurisdictions restrict polystyrene foodware or certain PFAS-treated packaging regardless of federal food-contact status, so a nationally compliant material can still be non-compliant in a specific city or state.
For recycled PET, know which recycling route you’re dealing with before you go looking for FDA paperwork. Mechanically recycled PET can carry a voluntary FDA letter of no objection, but it’s optional, not mandatory — ask for the underlying purity and testing data either way. Chemically (tertiary) recycled PET or PEN won’t have an individual FDA letter at all, because FDA has already determined those processes are pure enough and stopped reviewing them case by case — that’s not a compliance gap, it’s current FDA policy.
Reused container ‘downshifting’ — repurposing a #1 or #5 container from a non-food use into food service, or reusing single-use containers repeatedly — is a common source of food-safety incidents even when the original resin was compliant.
Explore more: More packaging compliance guides.
Plastic recycling numbers and food safety FAQs
Is plastic #5 (PP) safe for hot food and microwave use?
PP is commonly used for microwave-safe containers because of its heat resistance, but ‘microwave-safe’ depends on the specific product’s testing and labeling, not the resin number alone. Check the container’s labeling or the manufacturer’s spec rather than assuming based on the code.
Why is plastic #7 sometimes labeled unsafe and sometimes fine?
Because #7 covers a wide range of unrelated resins, including some formulations that use bisphenol A (BPA) and some that don’t. The safety of a #7 item depends entirely on which specific polymer it is, which the number itself doesn’t disclose.
Does recycled PET need FDA approval before it can touch food?
No, and the answer differs by recycling method. FDA doesn’t require premarket clearance for recycled plastic generally — the legal requirement is that the material be suitably pure for its intended use, which the manufacturer must document. For chemically recycled (‘tertiary’) PET and PEN specifically, FDA has already determined that processes like methanolysis and glycolysis produce sufficiently pure material, so it no longer reviews those processes individually or issues opinion letters for them. Mechanical recyclers can still request a voluntary letter of no objection from FDA as added assurance, but that has always been optional, not a mandatory approval.
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