The compliance of galvanized steel sheets in food contact scenarios depends on the control of zinc migration. The EU Food Contact Materials Regulation EC No1935/2004 stipulates that the limit for zinc ion migration is 5mg/kg of food (simulated substance test conditions: 3% acetic acid solution, 40℃, 24 hours). Experimental data from the German Federal Institute for Risk Assessment (BfR) shows that the median zinc precipitation concentration of Galvanized steel plates that comply with the EN10346 standard in an acidic environment (pH=4) is 1.2mg/dm², which is only 24% of the limit. Nestle Group’s 2021 supply chain audit report indicates that 32% of its global raw material handling equipment uses food-grade galvanized steel plates, and no incidents of zinc exceeding the standard have occurred over the past ten years.
Surface treatment processes are at the core of safety. Food-grade passivation requires the use of chromium-free conversion technology, with the film weight controlled at 0.5-2g/m² and the hexavalent chromium precipitation less than 0.01μg/cm² (FDA 21 CFR 175.300 standard). The FSIS test of the United States Department of Agriculture shows that after 24 hours of contact with meat, the zinc migration of silane-passivated galvanized sheets is only 0.8ppm, which is far below the safety threshold of 10ppm. The “Food Utensils Standards” revised by Japan’s Ministry of Health, Labour and Welfare in 2020 stipulates that galvanized sheets used for the inner walls of cans must pass 200 dishwasher cycle tests (82℃ hot water impact), with a zinc coating loss rate of less than 0.3μm per cycle.
Temperature adaptability determines the application scope. Pasteurization equipment (60-85℃) is recommended to use aluminum-zinc alloy coating (55%Al-Zn), whose zinc evaporation rate is 60% lower than that of pure zinc coating. The actual measurement data of Tetra Pak’s packaging production line shows that in a 90℃ hot filling environment, the zinc migration of Galvalume coated steel sheets remains at 0.5mg/kg after 3000 hours of use, while that of traditional galvanized sheets has reached 2.1mg/kg. In the cold storage scenario (-30℃), attention should be paid to the brittleness of the zinc coating. The ASTM A653 standard requires that the impact energy at -40℃ be ≥27J to avoid zinc chip shedding caused by cold brittleness.
The microbial control performance has been verified by authoritative authorities. The antibacterial environment formed by the release of zinc ions on the galvanized surface can reduce the survival rate of Escherichia coli by 99.7% (ISO 22196 test). A 2022 study by the UK Food Standards Agency (FSA) indicated that after meat processing plants switched to galvanized steel plate workbenches, the frequency of Listeria detection dropped from 3.2 times per month to 0.4 times. The epoxy zinc powder coating approved by the US FDA (thickness ≥80μm) can further suppress the bacterial growth rate to below 5CFU/cm², which is 90% lower than that of stainless steel surfaces.
Risks throughout the entire life cycle need to be systematically managed and controlled. The International Nickel Institute suggests that in scenarios where acidic foods (pH < 5) come into contact, zinc-nickel alloy coatings (containing 10-15% nickel) should be selected, which can enhance corrosion resistance by 300% and reduce zinc precipitation by 70%. The case of the pork processing plant of the Danish Crown Group shows that after adopting the nickel-zinc alloy coated conveyor belt, the frequency of equipment cleaning was reduced from three times per shift to once, saving 230,000 US dollars in disinfectant costs annually. It is necessary to ensure that the welding process complies with AWS D18.1 standard to avoid the acceleration of the local corrosion rate caused by zinc burn loss in the weld zone (up to 5 times the conventional zone).
The certification system ensures full traceability throughout the process. The NSF/ANSI 51 certification requires that galvanized sheets pass three rounds of migration tests (simulating a 10-year usage period), and the fluctuation range of zinc precipitation should be ≤±15%. According to the European food-grade steel certification system EFSA 10/2011, an ICP-MS test report (with a zinc element analysis accuracy of 0.01ppm) is required for each batch of materials. In 2023, a canning factory in Chennai, India, caused the zinc content in tomato sauce to exceed the standard by 3.7 times due to the use of uncertified galvanized sheets, resulting in a recall loss of 2 million US dollars. Compliant Galvanized steel plates, in combination with the HACCP system, can reduce the probability of food contamination risk to 0.003%.
Based on comprehensive food engineering practice, compliant galvanized steel sheets have significant advantages in scenarios such as normal temperature food storage with pH > 4 and neutral material transportation Its antibacterial performance reduces the risk of microbial contamination by 90%. The aluminum-zinc alloy coating keeps the zinc migration within 25% of the safety threshold in high-temperature environments. Combined with the chromium-free passivation process, it better meets the FDA’s strict regulation of 0.01μg/cm² chromium precipitation. By implementing ICP-MS testing per batch (with an accuracy of 0.01ppm) and AWS D18.1 welding standard, the total life cycle quality accident rate can be compressed to less than 0.003%, and the equipment maintenance cost is reduced by 70% compared with the stainless steel solution.