Monbento Tresor Bento Box
Lower concern bento box; no known PFAS-prone components.
Monbento Tresor uses ABS plastic containers, stainless steel utensils, and silicone gaskets. No coatings, nonstick finishes, or water treatments indicated; brand does not disclose PFAS status.
We flunk more products than we pass. This one earned its grade. How we grade
Material
ABS plastic, stainless steel, silicone gasket
Brand disclosure
Brand is silent on PFAS
Lab data
No public lab test
What Monbento Tresor Bento Box is made of, ingredients and materials
The Tresor uses ABS plastic for the main container and lid, stainless steel for hardware and internal structure, and a silicone gasket for the seal. ABS is a rigid, impact-resistant engineering plastic that does not contain BPA or BPS by formulation, though individual batches should be verified if sensitivity is a concern. Silicone gaskets are generally stable and inert under normal food-storage temperatures. Stainless steel is corrosion-resistant and does not leach metals into food under typical conditions.
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.
Microplastics
Repeated mechanical stress, dishwasher cycles, or scratching of the ABS can generate microplastics over many years; hand-washing and avoiding thermal shock reduce this risk.
Source, EPA ↗Bacterial or mold growth in gasket or seal
If the silicone gasket is not dried thoroughly or if the groove is not cleaned, moisture can harbor microorganisms; this is a use and maintenance issue rather than a material hazard.
What’s reassuring
Base material not linked to PFAS
The main material recorded for this product is not one associated with PFAS.
BPA & bisphenols
ABS formulation does not typically include BPA or BPS; however, Monbento has not published independent test reports or material certifications confirming absence for the Tresor specifically.
Source, FDA ↗Phthalates
Silicone gaskets and ABS plastic are not primary sources of phthalates, but ingredient-level verification for the Tresor is not publicly available from the brand.
Source, ATSDR ↗Metal leaching from stainless steel components
Food-grade stainless steel used in bento boxes does not leach nickel or chromium under normal storage; no published incidents for the Tresor have been identified.
The full breakdown
The brand's record and disclosure
Monbento has not published comprehensive materials disclosure or third-party certifications (e.g., FDA food-contact, EU food-contact compliance statements) on widely available product pages. The brand maintains a sustainability and design focus but does not prominently disclose PFAS, phthalate, or BPA testing results. No major product recalls have been established for the Tresor line regarding chemical migration or material degradation.
How it compares in its category
The Tresor occupies the mid-to-premium segment of plastic bento boxes. It avoids known PFAS-prone coatings and does not use non-stick treatments that introduce Teflon-type coating or ceramic enamels prone to lead or cadmium contamination. Compared to budget two-part plastic lunch boxes, the stainless steel components and engineered gasket represent a more durable construction, though this does not eliminate the intrinsic chemical profile of the plastic itself.
If you buy it
Hand-wash the container and lid rather than running them through a dishwasher to extend seal integrity and avoid high-temperature stress on the plastic and gasket. Do not expose the ABS to prolonged heat above 80 degrees Celsius (176 Fahrenheit), which can deform it; avoid microwaving the container with food inside. Inspect the silicone gasket annually for cracks, discoloration, or odor; replace it if compromised. Store dry and ensure the gasket dries fully to prevent bacterial or mold growth in the seal groove.
What we don’t know
- Basis
- Model estimate, 72% confidence, not a lab result
- Lab test
- None on record for this exact product
- Brand statement
- Monbento has made none
Formulations change between production runs, so check the current label. How we grade.
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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.