Every material gives something to your food.
What is Migration?
When food sits in a container, molecules from the container surface transfer into the food. This is called migration. It happens with every material — glass, plastic, silicone, steel, ceramic.
The question isn't whether migration occurs. The question is: what migrates, how much, and does it matter?
In the UK and EU, food contact materials are governed by EC 1935/2004, which requires that materials must not transfer their constituents to food in quantities that could endanger health.
What 304 stainless steel releases.
304 stainless steel contains chromium and nickel. Under certain conditions, trace amounts of these metals can migrate into food:
- At fridge temperature (cold storage) Migration is effectively zero. The amount of nickel that transfers to food during cold storage is below the natural nickel content already present in the food itself. For context: 100g of cashew nuts contains more nickel than a year's worth of cold storage in a steel container.
- At cooking temperature with neutral foods (pH > 5) Very low migration. Well within regulatory limits. This covers ~70-80% of meals — rice, pasta, meat, vegetables, most soups.
- At cooking temperature with acidic foods (pH < 5) This is the condition people worry about — so we test for it. For example, our stainless steel food containers are independently migration-tested under hot, acidic conditions — nothing detected. The report is on file — see below.
Our recommendation: Store anything at any temperature. Reheat and cook on the hob or in the oven — that's where this material shines.
The difference that matters.
There's a fundamental difference between what stainless steel releases and what plastic or silicone releases.
Stainless steel releases natural elements.
Nickel and chromium are elements — they exist in soil, water, and food naturally. The nickel ion (Ni2+) released from steel is the same ion you get from eating spinach, chocolate, or nuts. Your body has evolved to process these elements in small quantities.
Plastic and silicone release synthetic compounds.
Microplastics, bisphenols, phthalates, and cyclic siloxanes are synthetic — manufactured molecules with no natural equivalent. Your body has no evolved mechanism for processing them. Some are classified as endocrine disruptors.
What "stainless steel container" actually means on the market.
Look across mainstream stainless steel food-container listings. Many are stainless steel bodies with:
- Silicone gasket seals in the lid
- Plastic locking mechanisms
- Glass lids with silicone trim
- Non-stick coatings on the interior
The body is steel. But the part that touches your food most intimately — the seal, the lid surface — is silicone or plastic. Our products avoid this entirely. For example, our stainless steel food containers have no silicone anywhere: the lid is 304 stainless steel too — a mechanical friction fit, no gasket, just steel on steel. Laid flat it stays securely sealed; not fully airtight, so not for carrying liquids loose in a bag — but nothing synthetic ever touches your food.
Our claims are backed by third-party lab reports.
We commission the testing ourselves, from an independent, accredited third-party laboratory. For example, we submitted our stainless steel food container for two tests:
- Migration test — heavy-metal release. Metal release into a 0.5% citric-acid food simulant — the hot, acidic worst case — held at 100°C for 4 hours, analysed by ICP-OES and ICP-MS (with reference to EN 13130-1:2004) and assessed against EC 1935/2004 and the EDQM Technical Guide on Metals and Alloys in food-contact materials (2nd edition, 2024). Every one of the 22 metals tested came back **Not Detected**: aluminium, antimony, arsenic, barium, beryllium, cadmium, chromium, cobalt, copper, iron, lead, lithium, manganese, mercury, molybdenum, nickel, silver, thallium, tin, vanadium, zinc and zirconium. A separate odour-and-taste panel (DIN 10955:2024) found no perceptible difference. Result: **Pass**.
- Chemical composition analysis — is it genuinely 304? Elemental analysis of the steel (ASTM E1086-22), measured result against the 304 specification: chromium **18.17%** (spec 17.5–19.5), nickel **8.04%** (8.0–10.5), manganese 1.08% (≤2.00), silicon 0.47% (≤1.00), carbon 0.049% (≤0.07), nitrogen 0.050% (≤0.10), phosphorus 0.034% (≤0.045), sulphur 0.005% (≤0.015). Every element within spec — confirming BS EN 10088-1:2014 type X5CrNi18-10 (1.4301): genuine 304, the real 18/8.
Both reports are held on file. Email [email protected] and we'll send you the full documents.