Thermos Fresh Stainless Steel 1100ml Lunch Box in Line Black
Lower concern. Stainless steel core unlikely to contain PFAS.
Thermos lunch box uses primarily stainless steel, a bare material with low PFAS risk. Plastic lid and seals lack disclosure, but food-contact lunch containers rarely receive water-resistant coatings.
We flunk more products than we pass. This one earned its grade. How we grade
Material
Stainless steel body, plastic lid and seals
Brand disclosure
Brand is silent on PFAS
Lab data
No public lab test
What Thermos Fresh Stainless Steel 1100ml is made of, ingredients and materials
The Thermos Fresh lunch box uses a stainless steel exterior and interior vessel, which is chemically inert and does not leach metals or compounds into food under normal use. The lid and seals are plastic (likely polypropylene or similar), which are in contact with food but do not involve heating to temperatures that typically trigger leaching from these polymers. Stainless steel is a material not linked to PFAS, and degrades only under extreme acidic or salty conditions sustained over years.
What’s concerning
Category baseline
The starting point for this type of product, before anything specific to this product is counted.
No PFAS disclosure
No public statement from the brand about PFAS in this product.
BPA & bisphenols
Plastic lid and gasket materials are not certified BPA-free by the brand. Standard polypropylene (common in food lids) typically does not leach BPA, but the manufacturer does not explicitly disclose polymer type or additive chemistry.
Source, FDA ↗Phthalates
Plastic seals and lid may contain phthalate plasticizers, though modern food-grade plastics increasingly avoid them. No brand statement confirms phthalate-free formulation for this specific product.
Source, ATSDR ↗Microplastics
Repeated thermal stress, acidic foods, or mechanical wear can eventually degrade plastic seals into micro-fragments. Risk is low under normal care but increases if lids are microwaved or exposed to sustained heat.
Source, EPA ↗Mold or bacterial growth in seals
Plastic seals trap moisture and food residue if not thoroughly dried after washing. Damp seals can harbor mold or bacteria between uses, particularly if stored sealed in a warm environment.
What’s reassuring
Bare uncoated material
Recorded as a bare, uncoated material with no surface coating or treatment.
Stainless steel nickel release
High-quality stainless steel (typically 304 or 316 grade) releases negligible nickel under food contact conditions. No recalls or reports for this product exist; risk is theoretical only in individuals with severe nickel allergy and acidic food exposure over extended periods.
The full breakdown
The brand's record and disclosure
Thermos is a long-established brand (Thermos LLC, owned by Groupe SEB) with no major public recalls or safety controversies specific to this lunch box line. The company does not publicly disclose detailed material sourcing, supplier audits, or chemical testing results for this product. No third-party certifications (BPA-free, phthalate-free) are prominently advertised, which is typical for stainless steel food containers where such claims are less relevant than for plastic-heavy designs.
How it compares in its category
Stainless steel lunch boxes show lower concern regarding PFAS migration compared to plastic-only or plastic-lined containers. This product avoids the aluminum-lined or ceramic-coated designs that carry historical concerns about metal migration or coating degradation. It sits in the mid-to-premium tier for lunch boxes, where material quality and manufacturing standards are generally reliable, though without third-party certification it relies on brand reputation.
If you buy it
Hand wash the plastic lid and seals with warm soapy water; do not soak lids in boiling water as prolonged heat can degrade plastic seals over time. Do not fill with boiling liquids if the lid will seal immediately, as pressure buildup can stress plastic components. Inspect seals annually for cracks, discoloration, or hardening; replace the lid if seals become rigid or cloudy. Stainless steel body is durable for years; plastic components typically last 2-3 years of daily use before replacement is warranted.
What we don’t know
- Basis
- Model estimate, 78% confidence, not a lab result
- Lab test
- None on record for this exact product
- Brand statement
- Thermos has made none
Formulations change between production runs, so check the current label. How we grade.
Better-graded alternatives in Lunch Boxes
Klean Kanteen
Double Wall Vacuum Insulated Stainless Steel Food Canister Container with Leak Proof Lid
- Stainless steel body, silicone gasket lid seal
- The brand calls it PFAS-free, which we have not verified
- Silicone gasket degradation
3 hazards checked on this product. See all of them.
More lunch boxes 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.