UK What food grade stainless steel means
Food grade stainless steel is stainless steel that is safe to use in contact with food and drink and stands up to the cleaning a food plant demands. It does not absorb, taint or react with most foods, it has no coating to chip off, and it survives repeated hot washing and sanitising. That is why it is the default material for tanks, conveyors, worktops, fillers and the machinery around them.
The phrase is a description rather than one standard. Food-contact rules come from each market: in Europe, Regulation (EC) No 1935/2004 sets the framework for all food-contact materials, and in the United States, food equipment is commonly assessed to NSF/ANSI 51 for materials and to 3-A Sanitary Standards for dairy. These set requirements for the material and its finish, and the equipment maker shows compliance for its own product.
In practice, two grades cover almost all food production: 304 for general use and 316 where salt, acids or aggressive cleaning chemicals would attack 304.
Which stainless steel grades are food grade
Several grades are used in contact with food, but they differ a great deal in corrosion resistance. Grade numbers follow the AISI system, and the 18/8 and 18/10 labels on kitchenware give the chromium and nickel percentages.
| Grade | Type | Chromium / nickel | Food use | Watch for |
|---|---|---|---|---|
| 304 (18/8) | Austenitic | Around 18% / 8% | Most processing, packaging, bakery and catering equipment | Pitting from salt, brine and chlorides |
| 316 | Austenitic + molybdenum | Around 17% / 10 to 14%, plus 2 to 3% Mo | Dairy, meat, brines, sauces, daily chlorinated sanitising | Costs more than 304 |
| 430 | Ferritic | Around 17% / no nickel | Cutlery, appliance panels, dry-food contact | Lower corrosion resistance; magnetic |
| 201 | Austenitic, manganese-rich | Around 17% / 4 to 5% | Low-cost utensils and trim | Corrodes more readily; rarely used in food plants |
Our guide to 304 vs 316 stainless steel covers the two main grades in depth, including how they behave under different cleaning chemicals.
When to choose 316 over 304
304 is the sensible default for dry goods, bakery, confectionery and most packaging lines. 316 earns its higher cost where the environment would pit 304 within months:
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Salt and brine. Meat, fish, cheese and pickling lines, where salty product and process water sit on surfaces.
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Acidic product. Sauces, fruit juices and dressings with a low pH.
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Chlorinated sanitisers. Daily hypochlorite or chlorine dioxide sanitising, especially where it is left to dry on the surface.
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Hot, wet cleaning. Caustic and acid washes at high temperature, as used in dairy and in clean in place circuits.
Why surface finish matters as much as grade
A food grade alloy with a rough finish can still harbour bacteria. Scratches, pits, rough welds and crevices hold soil and biofilm where cleaning chemicals cannot reach. Hygienic design guidance, such as that published by EHEDG and 3-A, asks for smooth, continuous product-contact surfaces, typically with a roughness of around Ra 0.8 µm or better, fully welded and ground joints, rounded internal corners and shapes that drain.
The same thinking applies to everything in the splash zone. Exposed threads, gaps behind bezels and vents all collect product and cleaning water. Our guide to hygienic design for washdown computers covers what that means for HMIs and displays.
Fabrication also affects the result. Welding, grinding and contact with carbon-steel tools can leave heat tint or embedded iron that rusts and spoils the passive layer. Good fabricators clean and passivate stainless parts after working them, usually with a citric or nitric acid treatment, so the surface is fully protective before it reaches the line. Cleaning chemicals need the same care: strong chlorinated products left to dry, or hydrochloric acid descalers, will attack even 316, so follow the chemical supplier’s guidance on concentration, temperature and rinsing.
Food grade stainless steel in computers and HMIs
Line HMIs, scales, labellers and displays sit right next to the product and are foamed and hosed with the machinery around them. They are usually specified in the same 304 or 316 as the line, with a flat, sealed front, no fans or vents and sealed connectors. Where the line is cleaned with high-pressure hot water, the enclosure also needs an IP69K rating.
Our IP69K panel PCs and stainless steel monitors are built for washdown areas in food and beverage plants, in 304 or 316 depending on the model.
Quick answers on food grade stainless steel
Food grade stainless steel: common questions
Is 304 stainless steel food grade?
Yes. 304, also called 18/8, is the most widely used food-contact stainless steel. It suits most processing and catering equipment, but salt and chlorides can pit it, so 316 is better for brines and aggressive sanitisers.
Is 316 stainless steel food grade?
Yes. 316 is food grade and more corrosion resistant than 304 thanks to its molybdenum. It is the usual choice for dairy, meat, seafood and acidic products.
Is 18/8 stainless steel food grade?
Yes. 18/8 describes around 18% chromium and 8% nickel, which is grade 304. 18/10 is a similar austenitic grade with a little more nickel, often used for cookware.
Is food grade stainless steel magnetic?
It depends on the grade. 304 and 316 are essentially non-magnetic, although cold working can make them slightly magnetic. Ferritic 430 is magnetic. A magnet test tells you the family, not whether the steel is food safe.
Is 201 stainless steel food grade?
It can be used, but it is a poor choice for processing. 201 replaces some nickel with manganese, which lowers its corrosion resistance. It turns up in low-cost utensils, but food plants specify 304 or 316.
How can you tell if stainless steel is food grade?
Check the documentation. Look for the grade on the material certificate or datasheet and a food-contact declaration from the maker. Markings such as 18/8 or 304 help, but the paperwork is what an auditor will ask for.
We supply stainless steel panel PCs and monitors for food plants with the grade, sealing and mounting matched to the cleaning regime, and integrate and test each system before it ships. Tell us how the area is cleaned and with which chemicals, and we will recommend 304 or 316 to suit.