What are the key downstream applications and regulatory risks for sodium metabisulfite in China?

Sodium metabisulfite serves dual roles across food and industrial sectors. In food processing, it acts as a preservative, antioxidant, and bleaching agent for dried fruits, vegetables, wine, and shrimp—though overuse raises sulfur dioxide residues, a major food safety concern. In 2024, Chinese customs rejected 288 batches of imports for metabisulfite-related additive violations, with 286 involving South American white shrimp, highlighting strict enforcement. Industrially, it is used in water treatment, pulp and paper bleaching, textiles, mining flotation, concrete admixtures, and organic synthesis as a reducing agent. The downstream demand structure is shifting, with food-grade applications facing tighter regulatory scrutiny while industrial uses, particularly in water treatment and mining, provide steadier growth. Buyers must ensure compliance with national standards to avoid supply chain disruptions.