In the food industry, there are strict standards that manufacturers must follow to avoid contamination. Stainless steel is often used in food and beverage processing machinery or products, but not all stainless steel is food-grade. Only stainless steel that meets government safety standards, maintains the highest purity, and ensures quality is considered “food-grade.” Next, let’s explore the types of food-grade stainless steel used in food processing.
What is Food Grade Stainless Steel?
Food-grade stainless steel is a type of stainless steel that meets food safety standards. In tableware applications, such as plates, bowls, and utensils, it is non-toxic and harmless, and will not react with food to affect its taste or health. In food processing machinery, such as mixers and slicers, food-grade stainless steel has strong corrosion resistance, can resist the effects of water vapor and acidic or alkaline substances, and ensures the food processing process is safe and hygienic, providing reliable protection for the food industry.
What’s the difference between food grade stainless steel and regular stainless steel?
Stainless steel is the best material choice for the food industry and comes in different grades for use in food processing and other applications. However, not all stainless steel is food-grade.
Food-grade stainless steel must meet strict standards, which are considered safe for food contact, processing, preparation, and storage. These standards ensure it does not change the food’s taste, smell, or color, is non-toxic, and does not release harmful particles.
Differences in Composition
Food-grade Stainless Steel: For example, 304 stainless steel has at least 18% chromium, at least 8% nickel, and carbon content below 0.08%. 316 food-grade stainless steel also contains 2-3% molybdenum. These components give it strong corrosion resistance and prevent the release of metal ions.
Regular Stainless Steel: Has about 13% chromium, low or no nickel, and higher carbon content. This increases hardness but lowers toughness and corrosion resistance. Its composition is not as strict as food-grade stainless steel.
Composition
Food-grade Stainless Steel: For example, 304 stainless steel has at least 18% chromium, at least 8% nickel, and carbon content below 0.08%. 316 food-grade stainless steel also contains 2-3% molybdenum. These components give it strong corrosion resistance and prevent the release of metal ions.
Regular Stainless Steel: Has about 13% chromium, low or no nickel, and higher carbon content. This increases hardness but lowers toughness and corrosion resistance. Its composition is not as strict as food-grade stainless steel.
Corrosion Resistance:
Food-grade Stainless Steel: In food processing environments, it resists corrosion well when exposed to food, cleaners, and water. For example, it won’t be corroded by acidic substances in yogurt fermentation tanks.
Regular Stainless Steel: Has weaker corrosion resistance and can rust easily in damp, salty environments (like near the sea).
Safety
Food-grade Stainless Steel: The composition is stable, with almost no harmful metal ions leaching out during normal use. The surface oxide layer prevents chemical reactions, ensuring food safety.
Regular Stainless Steel: Due to its composition and manufacturing process, it may release metal ions when in contact with food, which can be harmful to health.
Surface Quality
Food-grade Stainless Steel: The surface is smooth and even, making it easy to clean and reducing bacterial growth. It is used in food processing areas like workstations.
Regular Stainless Steel: Surface quality varies depending on the use. For construction, it may have textured finishes, while industrial stainless steel may be rougher, just meeting basic functional needs.
Uses
Food-grade Stainless Steel: Used in equipment and tools that come into direct contact with food, such as processing machines, kitchen utensils, and storage containers. It ensures safe and hygienic food processing, storage, and transportation.
Regular Stainless Steel: Used widely in construction (doors, windows, curtain walls), automobiles (exhaust pipes), and machinery (machine shells). It is valued for its strength, toughness, and appearance, but it doesn’t meet the high food safety standards required in the food industry.
Common Food Grade Stainless Steels
304 Food-Grade Stainless Steel
304 stainless steel is the most commonly used material in the food processing industry. It is widely used in many food processing environments and provides an affordable option. It has strong corrosion resistance, especially against many oxidizing acids, which makes it easy to clean and disinfect.
The main composition of 304 stainless steel includes 18% chromium and 8% nickel, which makes it perform well in food processing. 304 stainless steel is often used in equipment such as storage tanks, fermentation tanks, and dishwashers because it resists corrosion from most acidic foods and liquids.
However, 304 stainless steel is not suitable for food processing environments that contain chlorides, as chlorides can cause corrosion.
316 Food-Grade Stainless Steel
316 stainless steel is a high-nickel, high-chromium austenitic alloy with even stronger corrosion resistance, especially in food processing that involves salty or acidic foods.
The composition of 316 includes 16-18% chromium, 10-14% nickel, and 2-3% molybdenum. The addition of molybdenum improves its resistance to chlorides and acids. This makes 316 stainless steel especially suitable for food processing environments that require frequent cleaning, such as meat processing plants.
316 stainless steel can withstand high temperatures and harsh corrosive environments, making it ideal for storing and processing foods with high salt content. Although 316 stainless steel is more expensive than 304, its superior corrosion resistance makes it more reliable for use in special food processing environments.
430 Food-Grade Stainless Steel
430 stainless steel is a ferritic stainless steel with lower nickel content, which makes it less expensive than 304 and 316. Its chromium content is similar to 316, but due to the lower nickel content, its corrosion resistance is relatively weaker.
430 stainless steel has strong resistance to organic acids and nitric acid, making it suitable for applications where it will come into long-term contact with weak acidic substances. It is commonly used in vegetable processing plants and is suitable for countertops, tables, and other food processing equipment where lower corrosion resistance is acceptable.
However, due to its lower corrosion resistance, 430 stainless steel is not suitable for processing foods with high salt or acid content.
430 stainless steel is a ferritic stainless steel with lower nickel content, which makes it less expensive than 304 and 316. Its chromium content is similar to 316, but due to the lower nickel content, its corrosion resistance is relatively weaker.
430 stainless steel has strong resistance to organic acids and nitric acid, making it suitable for applications where it will come into long-term contact with weak acidic substances. It is commonly used in vegetable processing plants and is suitable for countertops, tables, and other food processing equipment where lower corrosion resistance is acceptable.
However, due to its lower corrosion resistance, 430 stainless steel is not suitable for processing foods with high salt or acid content.
Advantages of Food Grade Stainless Steel
Significant Ingredient Advantages
Stainless steel is an alloy of iron, carbon, and at least 10.5% chromium. The chromium forms a protective layer that resists corrosion, while nickel, molybdenum, and other elements further enhance its performance. This combination gives it many excellent qualities, making it stable, durable, and safe for food contact. It ensures the quality and safety of food processing and lays a strong foundation for its advantages in the food industry.
Strong Corrosion Resistance
With a high chromium content, stainless steel forms an oxide layer that protects against corrosion. It does not rust easily when exposed to heat, water, or cleaning agents, and can self-repair if scratched. This ensures food contact safety and extends the lifespan of equipment.
Safe and Reliable
It contains no harmful chemicals and meets FDA requirements for food processing equipment. It is durable, non-absorbent, and has no pores, preventing the migration of substances or the absorption of odors, ensuring food remains uncontaminated and safe.
High Strength and Durability
Stainless steel is strong and can withstand heavy use in the food industry, including friction, impact, and changes in temperature. It doesn’t easily deform or break, offering long-term, stable use and reducing replacement costs.
Easy to Clean:
The smooth surface is easy to clean and disinfect, preventing bacteria from growing. It can handle frequent use of harsh cleaning agents without retaining food odors, maintaining a hygienic food processing environment.
Non-reactive Surface:
It does not absorb colors, odors, or chemicals. In cooking and commercial use, it prevents cross-contamination and keeps the original taste of food, making it ideal for various food processing applications.
Low Maintenance Cost
Due to its stable physical and chemical properties, stainless steel equipment requires minimal maintenance over time. There’s no need for complex upkeep, saving labor and resources and reducing overall costs.
Attractive and Versatile
Stainless steel has a shiny, attractive appearance and a range of mechanical properties. It can be made into various food service products with different finishes. It is waterproof and prevents contamination, meeting both aesthetic and functional needs in the food industry.
Applications of Food-Grade Stainless Steel
Food-grade stainless steel has a wide range of applications in the food industry:
Food Processing Equipment
Processing Machinery
Machines like mixers, dough kneaders, and slicers are often made with food-grade stainless steel. Food-grade stainless steel, such as 304 or 316, ensures the equipment’s durability and helps maintain food safety.
Conveyor Pipes
In food processing plants, pipes used to transport liquid foods (such as juice, milk, and cooking oil) and semi-liquid foods (like sauces and jams) are often made from food-grade stainless steel. Stainless steel pipes have smooth surfaces that reduce food residue and bacterial growth, ensuring the purity of the food.
Fermentation Equipment
In food production places like breweries and yogurt factories, fermentation tanks are core equipment. Fermentation tanks made from food-grade stainless steel (like 304) can resist the acidic substances produced during fermentation and withstand temperature changes. Their good sealing also prevents the entry of external bacteria, ensuring the quality of fermented products.
Food Storage Containers
Storage Tanks
In the food industry, large amounts of liquid foods (like cooking oil and beverage concentrates) and solid foods (such as flour and sugar) need to be stored in tanks. Food-grade stainless steel storage tanks (like 304 or 316 stainless steel) prevent chemical reactions between the food and the tank, avoiding food contamination.
For example, stainless steel tanks used for storing cooking oil can resist oxidation and spoilage, extending the shelf life of the oil. Stainless steel tanks used for storing sugar can prevent the sugar from absorbing moisture and spoiling.
Fresh-keeping Boxes and Sealed Containers
Food-grade stainless steel fresh-keeping boxes and sealed containers are widely used in homes and the food service industry. These containers can store leftovers, fresh ingredients, and other foods. Food-grade stainless steel is safe and non-toxic, unlike some plastic containers that may release harmful substances when exposed to high temperatures or used for long periods.
Kitchen Utensils
Cooking Tools
Many cooking tools, such as pots and pans, are made from food-grade stainless steel.
Tableware
Tableware like plates, bowls, and chopsticks are also commonly made from food-grade stainless steel.
Tableware made from 430-grade stainless steel offers decent corrosion resistance at a lower cost. These utensils do not react with food, ensuring that the taste and color of the food remain unchanged. They are also easy to clean and disinfect, ensuring hygiene and contributing to the health of the people using them.
Production Processes of Food-Grade Stainless Steel
Casting Process in the Food Industry:
The stirring paddles of food mixers are often made using investment casting. This method ensures precision and corrosion resistance, and prevents metal from leaching into the food during mixing. Similarly, milk storage tank bodies are made using sand casting, which meets strength and sealing requirements to ensure food storage safety.
Machining Process in the Food Industry
The drive shafts of food packaging machines are turned to ensure precision and stability, while milling is used for mounting parts to ensure accurate packaging. Stove burner supports are drilled and milled to provide support for cookware, resist corrosion, and ensure no harmful substances are released during cooking, guaranteeing safe use.
Cutting Process in the Food Industry
Food-grade stainless steel is often cut using laser and plasma cutting methods. Laser cutting is highly precise and creates smooth edges, making it ideal for producing utensils. Plasma cutting is faster and can cut thick plates, making it suitable for the initial cutting of large storage tanks to meet different processing needs.
Welding Process in the Food Industry
Tungsten inert gas (TIG) welding is the preferred method for welding food-grade stainless steel. The use of argon gas prevents oxidation, ensuring that welds on equipment like pipes and fermentation tanks are corrosion-resistant and safe for food contact.
Bending Process in the Food Industry
Bending machines are used to bend food-grade stainless steel. The bending parameters are adjusted according to the material thickness. For example, when making storage containers, the bending parameters of 304 and 316 stainless steel need to be carefully controlled to ensure both quality and appearance are maintained.
Surface Treatment Process in the Food Industry
Polishing is common, with both mechanical and electrochemical polishing used to create smooth and shiny surfaces, such as for tableware and kitchen tools. Passivation treatment is also used to form an oxide layer that enhances corrosion resistance, ensuring the stability of the material in food environments.
Contact Manck Casting for Food-Grade Stainless Steel Metal Solutions
Food-grade stainless steel is an ideal choice for various food processing applications, offering features such as corrosion resistance, heat resistance, durability, neutrality, and ease of disinfection.
Since 1998, Manek Casting has been supplying and processing stainless steel and other metals, including casting, machining, and other processes.
We provide a wide range of stainless steel parts and products for the food industry, including food-grade mechanical components, pipes, and precision cut parts to meet your application needs.
