Although all stainless steels are corrosion resistant, not all stainless steels meet food grade requirements. Food grade stainless steels have strict standards for composition, corrosion resistance, processing methods, and hygienic safety. We will describe them in detail in the article.
What Is Food Grade Stainless Steel?
"Food grade stainless steel" refers to specific stainless steel materials that meet food safety and sanitation requirements. Food grade stainless steel has extremely high corrosion resistance and does not react with food or beverages, which can ensure the safety of food during processing, storage and transportation. Therefore, food grade stainless steel must not only meet the physical and chemical performance requirements of the material, but also meet specific hygienic standards. The most commonly used food grade stainless steel materials are 304 stainless steel and 316 stainless steel.
Why Is Stainless Steel a Safe Choice For The Food Industry?
In the food industry, the choice of materials directly affects the quality, safety and health of food. Especially in the processing, storage, transportation and other links of food, using the right materials can not only improve production efficiency, but also ensure food hygiene and safety.
For any material to be considered food grade, it must meet certain conditions that meet FDA guidelines. In other words, the material must have certain mechanical properties that comply with all food handling processes specified by the FDA. The material itself must be durable, corrosion-resistant, non-absorbent, and non-porous. Its weight and thickness must be able to withstand repeated washing and rinsing. Food-grade materials must have smooth surfaces to allow for easy cleaning and disinfection of the surface. In addition, the material must be resistant to chipping, scratching, nicking, denting, warping, deformation, and decomposition. Finally, the material properties must prevent the migration of harmful substances or the transfer of any odor, taste, or color to food.
The inherent properties of stainless steel alloys, including corrosion resistance, make them very suitable for use in liquids and foods, especially 304 and 316 stainless steels, which can form a passivation film by adding elements such as chromium (Cr), nickel (Ni), and molybdenum (Mo) to effectively prevent oxidation and corrosion. Even in environments where they are in contact with acidic or alkaline foods for a long time, stainless steel can still maintain good corrosion resistance and will not release substances that are harmful to the human body.
Characteristics And Performance Of Food-Grade Stainless Steel
In order to ensure the safety and hygiene of food, food-grade stainless steel usually has the following characteristics:
- Corrosion resistance: During food processing, many foods and beverages contain acids, salts, oils and other chemicals. Ordinary stainless steel may corrode and release harmful substances due to contact with these substances. Food-grade stainless steel, such as 304 and 316, is not only resistant to oxidation, but also resistant to the erosion of most acidic and alkaline substances and salts.
- High temperature resistance: Many food processing processes involve high temperatures, such as baking, boiling, steaming, etc. In these high-temperature environments, food-grade stainless steel can maintain its mechanical properties and surface stability, and will not deform or oxidize due to excessive temperatures.
- Easy to clean: The surface of food-grade stainless steel is smooth and not easy to absorb stains or bacteria. It is easy to clean and meets the requirements of food hygiene. During processing, storage and transportation, stainless steel equipment with good surface treatment can reduce bacterial growth and avoid cross contamination.
- Non-toxicity and biocompatibility: Food-grade stainless steel must ensure that it does not release toxic substances when in contact with food, such as harmful metals such as lead, cadmium, and copper. Therefore, food-grade stainless steel must comply with relevant hygiene and safety certification requirements to ensure that its material is harmless to the human body.
Food Safety Stainless Steel Grade
In our daily life, the more common food-grade stainless steels include 304 stainless steel and 316 stainless steel.
304 stainless steel is composed of 18% chromium (Cr) and 8% nickel (Ni). It has excellent corrosion resistance, oxidation resistance and weldability and is widely used in food processing equipment, kitchen utensils, beverage containers, tableware, etc.
Advantages of 304 stainless steel:
- Corrosion resistance: 304 stainless steel has excellent corrosion resistance and can resist the erosion of most acids, salts and greases.
- Oxidation resistance: Even under high temperature conditions, 304 stainless steel can maintain stable performance and is not easy to oxidize.
- Non-toxic and harmless: 304 stainless steel is a food-grade material that will not react with food, will not release harmful substances, and meets food safety standards.
- Easy to clean: 304 stainless steel has a smooth surface, is easy to clean and disinfect, and is not easy to accumulate bacteria or stains.
316 stainless steel has higher corrosion resistance than 304 stainless steel, especially in high salt and high chloride environments. 316 stainless steel adds molybdenum (Mo) to 304. The addition of molybdenum significantly enhances its ability to resist chloride corrosion. Therefore, 316 stainless steel is suitable for more demanding food processing environments, especially in seafood, dairy products and chemical processing.
Advantages of 316 stainless steel:
- Stronger corrosion resistance: 316 stainless steel shows better corrosion resistance in acidic, high salt or chlorine-containing environments, suitable for seafood, brewing, dairy products and other industries.
- High temperature resistance: 316 stainless steel has excellent high temperature resistance and can withstand high working temperatures, suitable for high temperature food processing.
- Antimicrobial resistance: Similar to 304 stainless steel, 316 stainless steel has good antimicrobial ability and is suitable for food processing environments that require high hygiene standards.
As a key material in the food industry, stainless steel has become the preferred material for food processing, storage and transportation due to its corrosion resistance, high temperature resistance, easy cleaning and good hygiene. However, not all stainless steel is suitable for food contact, and stainless steel that meets food grade standards must be selected to ensure food safety. Among them, 304 and 316 stainless steel are common types of food grade stainless steel.
