Monbento MB Square Bento Box
Lower concern; rigid bento box with no known PFAS-associated coatings or treatments.
Monbento MB Square uses polypropylene and stainless steel construction. No applied water-repellent or nonstick coatings documented; brand does not disclose PFAS status but materials pose lower PFAS risk.
We flunk more products than we pass. This one earned its grade. How we grade
Material
Polypropylene (PP) and stainless steel
Brand disclosure
Brand is silent on PFAS
Lab data
No public lab test
What Monbento MB Square Bento Box is made of, ingredients and materials
The Monbento MB Square uses food-grade polypropylene (PP, #5 plastic) for the main container body and stainless steel for internal dividers. PP is a thermoplastic polymer that does not contain BPA or phthalates by formulation. Its melting point is around 130°C, so it remains stable for cold and warm (not hot) foods; prolonged exposure to very hot liquids or dishwasher heat cycles can cause gradual stress and micro-damage, though not rapid degradation or chemical leaching at normal use temperatures.
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 dishwashing and thermal stress can cause micro-scale cracking and particle shedding from PP, especially if heated above safe thresholds or subjected to abrasive scrubbing. Risk increases with product age and misuse but is not unique to this brand.
Source, EPA ↗What’s reassuring
Base material not linked to PFAS
The main material recorded for this product is not one associated with PFAS.
BPA & bisphenols
Polypropylene formulation does not inherently contain BPA or BPS. No public test data or brand disclosure confirms or denies presence of other bisphenol analogues (BPF, BPM) in this specific product.
Source, FDA ↗Phthalates
PP does not typically require phthalate plasticizers; they are more common in PVC and polyvinyl chloride products. No established record of phthalate presence in Monbento bento boxes.
Source, ATSDR ↗Coating or surface treatment toxins
No documented glazes, enamels, or chemical coatings are applied to the PP body in standard Monbento MB Square design. Stainless steel dividers do not use decorative or protective coatings that are publicly disclosed.
Seal and gasket material safety
The silicone or elastomer gaskets used to seal the lid are not publicly detailed by brand; silicone is generally lower-concern, but specific material composition and any processing chemicals are not disclosed in available product information.
The full breakdown
The brand's record and disclosure
Monbento is a French food-storage brand with a stated focus on sustainable and healthful design; they emphasize stainless steel components to minimize plastic contact. The brand does not publicly disclose comprehensive third-party testing (BPA, BPS, or other endocrine disruptors) or formal material certifications (e.g., NSF, EU compliance statements are not readily available in public marketing). No established product recalls or safety controversies for this line are on record.
How it compares in its category
Most rigid bento boxes are PP or polycarbonate; this model's use of PP avoids the BPA risk associated with polycarbonate. The inclusion of stainless steel compartments reduces overall plastic-food contact compared to fully plastic alternatives. It is less expensive than all-glass or all-stainless alternatives, but offers comparable chemical stability for cold and room-temperature foods. Leaching risk is lower than silicone or polyvinyl chloride-based storage containers.
If you buy it
Hand wash or use the top rack of a dishwasher on cooler cycles; repeated high-heat dishwashing can cause stress cracking and seal degradation over 1, 2 years. Do not fill with hot liquids above 70°C or microwave for extended periods; use it for cold, chilled, and lukewarm foods. Inspect the container annually for visible cracks, cloudiness, or loss of seal; replace if damage is evident. Stainless steel dividers do not require special care but should be rinsed promptly to prevent any residual moisture staining.
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
- 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.