5 Things You Need To Know About Food-Grade Stainless Steel

1: The Steel’s Finish Can Affect its Suitability for Food Processing

Stainless steel is famous for being able to resist corrosion, but just because the surface of the steel looks shiny and smooth doesn’t mean that it’s food-grade.

To meet key sanitary standards, the finish of the steel MUST eliminate any surfaces that could result in bacterial growth while being easy to clean/sanitize.

Here, processes such as electropolishing are favored over manually grinding down surfaces. The reason for this is that electropolishing strips away the surface layer of steel to reveal a microscopically-smooth substrate.

This not only enhances the strength of the oxide layer in stainless steel; it removes the microscopic flaws in a surface that could harbor bacteria.

2: Stainless Steel Should NEVER Be Cleaned with a Plain Steel Brush

Steel wire brushes are a popular choice for cleaning deep-set stains from metal surfaces. However, such brushes should NEVER be used to clean a stainless steel object.

Particles from the plain steel in the brush could become imbedded in the surface of the stainless steel, compromising the integrity of the protective oxide layer. Over time, this will allow the “stainless” steel to rust like ordinary steel.

Additionally, you should avoid using the same tools to clean both stainless and ordinary steels. Particles picked up from the plain steel could transfer to the stainless.

3: Not All Food-Grade Stainless Steel Alloys Are Created Equal

Just because a steel alloy is marketed as being “food grade” doesn’t mean it’s the right material for your production process.

There are a number of different stainless steel alloys on the market, each with its own strengths and weaknesses when it comes to resisting specific chemicals and production environments.

For example, salt is known for being exceptionally corrosive to metal compounds. While grade 304 stainless steel is resistant to most corrosives, prolonged exposure to salt can still eat away at it. So, grade 304 stainless wouldn’t be suitable for any process requiring repeated, prolonged exposure to salt or saltwater.

Grade 316 stainless, on the other hand, is much more resistant to salt exposure than grade 304. This makes grade 316 stainless steel preferable for food makers that use salt or saltwater in their products.

4: Temperature Extremes CAN Affect Food-Grade Stainless Steel

Most stainless steels have a melting point well outside of the temperature ranges typically employed in any food manufacturing process. However, it is still important to be careful of temperature extremes in your manufacturing process when selecting a food-grade stainless steel (and any potential coatings for it).

5: Welding Can Alter the Properties of Stainless Steel Alloys

The heat stress applied during some welding processes (as well as the use of dissimilar filler materials) can strip the protective oxide layer that gives food-grade stainless steel alloys their resistance to corrosion. This, in turn, can make metal forms that have been welded improperly start to corrode faster than they should.