How does stainless steel perform in terms of corrosion resistance in the food processing industry

In the food processing industry, the corrosion resistance of stainless steel is outstanding. The following provides an analysis from various aspects: 

General food processing environment

Acid-base environment: Many foods such as fruits, vegetables, and meats exhibit certain acidity or alkalinity during processing. The chromium element in stainless steel forms a dense oxide chromium passivation film on the surface, which can effectively resist the erosion of common acidic and alkaline substances. For example, in juice processing, containing acidic components like citric acid, 304 stainless steel equipment and pipelines can maintain good corrosion resistance and will not be rapidly corroded due to contact with juice, ensuring the service life and food safety of the equipment.

Wet environment: Food processing workshops usually have high humidity. In this humid environment, ordinary metals are prone to rust, but stainless steel can prevent the reaction between oxygen in the air and the metal substrate due to its passivation film, thus avoiding rusting. For instance, in the seafood processing workshop, the environment is often humid, and stainless steel workbenches, shelves, etc., can well resist the corrosion of the humid environment and maintain their performance and appearance.

Special food processing environment

High-salt environment: In the processing of pickled foods and other products, high-salt environments have strong corrosiveness. Generally, 304 stainless steel may experience pitting corrosion in high-salt environments, but 316 stainless steel, due to the addition of molybdenum, can significantly improve its corrosion resistance to chloride ions. In high-salt food processing, such as pickling pickles and salted fish, 316 stainless steel containers, mixing equipment, etc., can effectively resist salt corrosion and reduce the risk of equipment damage and metal ion leaching.

High-temperature environment: In food processing steps such as high-temperature sterilization and baking, stainless steel not only has to withstand high temperatures but may also come into contact with steam, grease, etc. Stainless steel can still maintain the stability of its passivation film at high temperatures and has good high-temperature oxidation resistance. For example, in high-temperature steam sterilization equipment, stainless steel can withstand the repeated action of high-temperature steam and will not suffer severe corrosion due to the combined effects of high temperature and humidity; in baking equipment, stainless steel baking trays and other facilities are not easily corroded by food substances such as grease in the high-temperature environment, ensuring the quality and safety of food processing.

Cleaning and disinfection process

Chemical disinfectants: The food processing industry needs to regularly clean and disinfect equipment and utensils. Common disinfectants such as chlorine-containing disinfectants and hydrogen peroxide have certain oxidizing properties. Stainless steel has good tolerance to these disinfectants, and its passivation film can resist the oxidation effect of disinfectants, thus not being severely corroded due to frequent disinfection. However, when using chlorine-containing disinfectants, if the concentration is too high or the contact time is too long, it may cause certain corrosion to stainless steel. Therefore, the concentration and action time of the disinfectant need to be controlled properly.

Mechanical cleaning: During mechanical cleaning using high-pressure water guns, brushes, etc., the surface of stainless steel may be slightly worn, but as long as it is not excessive wear that destroys the passivation film, stainless steel can still rely on its self-repair ability to form a passivation film again at the worn area and maintain its corrosion resistance.