Differences Between Industrial-Grade and Food-Grade Sodium Metabisulfite and Their Applications

Differences Between Industrial-Grade and Food-Grade Sodium Metabisulfite and Their Applications

Quality Standards:
• Purity: Both grades generally require a minimum purity of 96.5%, but food-grade purity is more strictly controlled. For example, the iron content in industrial-grade sodium metabisulfite is required to be below 50ppm, while in food-grade it must be below 30ppm. Industrial-grade has no specific requirements for lead content, whereas food-grade limits lead content to 5ppm.
• Clarity: Food-grade sodium metabisulfite must meet clarity standards, while industrial-grade has no such requirement.
• Microbial Indicators: Food-grade has strict requirements for microbial safety to ensure it is safe for food processing. Industrial-grade typically does not have these requirements.

Production Process:
• Raw Material Selection: Food-grade sodium metabisulfite requires raw materials that meet food safety standards to prevent contamination by harmful substances.
• Production Environment: Food-grade production must meet food safety standards, including cleanroom conditions and equipment requirements to avoid contamination. Industrial-grade focuses more on production efficiency and cost control, with less emphasis on environmental conditions.

Applications:
• Food-Grade Sodium Metabisulfite: Commonly used in food processing as a bleaching agent, preservative, and antioxidant to enhance color, texture, and shelf life. It is widely applied in products such as wine, beer, fruit juices, canned foods, candied fruits, pastries, and biscuits.
• Industrial-Grade Sodium Metabisulfite: Mainly used in industrial processes, including dyeing, papermaking, textile printing, leather tanning, and organic synthesis. It is also employed as a reducing agent in water treatment, flotation agent in mining, and an early strength agent in concrete.