Zojirushi Sz-MB04-BA
Lower concern. Bare stainless steel container, no known PFAS coatings.
Zojirushi SZ-MB04-BA is a stainless steel food storage container with no applied coatings or treatments disclosed. Stainless steel itself poses lower PFAS concern, though the brand provides no explicit PFAS statement.
We flunk more products than we pass. This one earned its grade. How we grade
Material
stainless steel food container
Lab data
No public lab test
What Zojirushi Sz-MB04-BA is made of, ingredients and materials
The Zojirushi SZ-MB04-BA is a stainless steel food container with no ceramic, enamel, or non-stick coating on food-contact surfaces. Bare 18/8 stainless steel (or similar food-grade alloy) does not leach lead, cadmium, or other heavy metals under normal storage and use conditions. The material is chemically inert to most foods and liquids, making it one of the lowest-concern material choices for food storage.
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.
Seal gasket or lid material leaching
The product likely includes a rubber or silicone gasket and a lid (material not specified in context). Rubber gaskets can occasionally off-gas odors or small amounts of volatile organics, but documented health hazards are rare. Silicone is inert. No specific recalls are on record for this SKU.
Bacterial growth in seams or around lid
All sealed food containers carry minor risk of bacterial colonization if not cleaned thoroughly, especially around the gasket and lid threads. This is a maintenance issue, not a material hazard, and is managed by regular washing.
Thermal injury from hot contents
Stainless steel conducts heat efficiently, so the exterior may become hot if filled with boiling liquids. This is a normal use hazard, not a defect, and is managed with care and awareness.
What’s reassuring
Base material not linked to PFAS
The main material recorded for this product is not one associated with PFAS.
Stainless steel leaching (iron, nickel, chromium)
Food-grade stainless steel does not leach these metals into food under normal storage conditions. Migration is extremely low and not a documented concern for this product category.
Coating degradation and flaking
This product has bare stainless steel interior surfaces with no ceramic, enamel, or non-stick coating. No coating degradation hazard is present.
The full breakdown
The brand's record and disclosure
Zojirushi is a Japanese consumer products company with a longstanding reputation in food containers and kitchen appliances. The company does not publicize detailed hazard testing or transparency reports for individual SKUs, but has no documented recalls or safety controversies specific to this product line related to coating degradation or leaching. Lack of public PFAS stance is typical for this category and does not indicate a problem.
How it compares in its category
Bare stainless steel containers rank among the lowest-concern food storage options alongside glass. This avoids the coating-degradation and leaching risks associated with ceramic-lined, enamel-coated, or plastic-lined containers. The trade-off is durability of any internal lining (if present) and thermal conductivity; stainless steel conducts heat faster than some insulated alternatives, which is typically a feature, not a hazard.
If you buy it
Clean with mild soap and water; stainless steel is durable and tolerates normal dishwashers. Avoid prolonged contact with highly acidic foods (vinegar, citrus, tomato) if the container will be stored for days, as prolonged acid exposure can cause minor surface pitting, though this does not create a health hazard. Inspect the seal gasket (if present) periodically for degradation and replace if cracked or hardened. Do not use abrasive scrubbers that damage the surface finish.
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
- Zojirushi has made a specific claim
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.