Ziploc · Food Storage Containers
Ziploc Twist 'n Loc Lunch and Meal Prep Food Storage Containers
Lower-concern food storage; rigid PP containers historically not treated with PFAS, but no brand disclosure.
Ziploc's Twist 'n Loc containers are made from rigid polypropylene, a plastic not typically requiring grease-resistant or stain-resistant coatings. Unlike some food-contact packaging (e.g., takeout liners, microwave popcorn bags), solid PP containers lack the conditions that usually trigger PFAS application.
Shop Ziploc on Amazon →Material
polypropylene (PP) rigid plastic container
Brand disclosure
Brand is silent on PFAS
Lab data
No public lab test
Why this grade
Category baseline
food packaging is a category where PFAS exposure is more common.
No PFAS disclosure
No public statement about PFAS in this product.
Safe base material
Made from a material with no inherent PFAS use (ceramic, mineral, or natural fiber).
The full breakdown
What it's made of and why it matters
Ziploc Twist 'n Loc containers are rigid polypropylene (PP), a thermoplastic that does not contain BPA or other intentional endocrine disruptors in its base formulation. Polypropylene is one of the more chemically stable food-contact plastics and resists leaching under normal conditions. The closure mechanism uses the same material, reducing multiple plastic types in the system. Heat tolerance is the critical boundary: PP softens around 140°F (60°C) and can warp or leach oligomers if exposed to sustained higher temperatures.
The brand's record and disclosure
Ziploc (owned by S.C. Johnson) does not publish detailed material safety or chemical disclosure reports for individual product lines. No major food safety recalls linked to chemical leaching from Twist 'n Loc containers appear in FDA or CPSC databases. The brand has faced occasional criticism for opacity on chemical additives and PFAS use in other product categories, but rigid food storage containers are not flagged as a concern area. S.C. Johnson maintains BPA-free labeling on most modern food storage lines.
How it compares in its category
Rigid polypropylene containers occupy the mid-range of food storage safety. Glass alternatives (e.g., Pyrex, OXO) eliminate plastic leaching entirely but are fragile and heavier. Other polypropylene brands (Rubbermaid, Sistema) have similar chemical profiles and comparable price points. Silicone or stainless steel options pose negligible leaching risk but cost more. Ziploc's snap-lock design is convenient but does not meaningfully reduce chemical hazards compared to competitors.
If you buy it
Use containers for room-temperature or refrigerated storage; avoid the oven, microwave on high heat settings, and dishwasher heated dry cycles. Hand wash or use gentle dishwasher cycles to extend seal integrity and reduce microscopic stress fractures where leaching can initiate. Replace lids and containers if clouding, cracking, or permanent warping appears, as degraded plastic is more likely to release oligomers. Store acidic foods (citrus, vinegar, tomato) separately, as acid marginally increases PP leaching, though risk remains low at typical concentrations.
Beyond PFAS: other things we checked
Established hazard classes for this product type, assessed from public information. These never change the PFAS grade; a Likely flag caps the Verdict at “Buy with care.”
BPA and BPS
Ziploc Twist 'n Loc containers are marketed as BPA-free, and polypropylene formulations do not require BPA as a base component. No recalled batches or confirmed leaching incidents are on record.
Phthalates
Polypropylene does not require phthalate plasticizers; rigid PP structures achieve strength without them. Phthalate risk is standard only for flexible PVC or soft plastics, not present in this product line.
Microplastics from degradation
Repeated heating, freeze-thaw cycles, or mechanical stress can cause microscopic PP fragmentation. Risk is low under normal refrigerator storage but increases if containers are heated above 140°F or used in aggressive dishwashers over many cycles.
Oligomer leaching from PP
Polypropylene sheds trace oligomers (incomplete polymers) under heat, acid, or prolonged contact with fatty foods. Concentrations in food storage are considered below regulatory concern limits, but risk scales with container age and thermal stress.
Additive migration (colorants, UV stabilizers)
Ziploc containers use food-grade pigments and stabilizers approved by FDA Title 21 CFR 177. No specific migration issues are documented, though ingredient lists are not publicly detailed by the manufacturer.
What we don’t know
This grade is a model-based estimate from public materials, coatings, and brand disclosure at 78% confidence. It is not a lab result.
No independent PFAS lab test is on record for this exact product. A lab test could move the score in either direction.
The brand has not made a specific, verifiable PFAS-free statement, so part of this score reflects that missing disclosure rather than a confirmed material.
Formulations and coatings change between production runs. Always check the current label before buying.
Safer alternatives in Food Storage Containers
Caraway
Food Storage Set
Glass containers with plastic lids
Lower concern; glass + plastic lids with stated PFAS-free position, but no third-party verification of lid material.
⚠Risky category by default
Caraway
Home 9-Piece Mini Food Storage Set
Borosilicate glass containers with plastic lids
Lower-concern option; glass containers avoid PFAS coatings, but verify lid material before purchase.
⚠Risky category by default
Caraway
Cream 6.6-Cup Non-Stick Glass Food Storage Container with Lid
borosilicate glass with non-PFAS lid
Lower PFAS concern, glass container with stated non-PFAS lid, though third-party verification absent.
⚠Risky category by default
More food storage containers grades
How we score: every product runs through the same public 0–100 rubric based on materials, coatings, brand disclosure, lab findings, and recalls. See the full methodology → Spotted a mistake? Report an error.