Classification
Product TypeIngredient
Product FormPowder/Crystalline (typically anhydrous)
Industry PositionFood additive (sulfiting agent) and industrial inorganic chemical
Market
Sodium sulfite (INS 221) is used in the United States as a regulated sulfiting agent in food manufacturing (antioxidant/preservative) where permitted, and it is also widely traded as an industrial inorganic chemical. U.S. market access hinges on compliance with FDA use limitations (including specific prohibited uses) and on labeling/ingredient-declaration expectations for sulfites in finished foods. For import flows when treated as food/food additive, FDA Prior Notice and CBP entry processes are key operational requirements. Because sulfites can trigger allergic-type reactions in susceptible individuals, undeclared or misused sulfiting agents are a recurrent enforcement risk in the U.S. context.
Market RoleDomestic producer and importer (food and industrial grades)
Domestic RoleManufacturing input for food processing (as permitted sulfiting agent) and for non-food industrial applications as a reducing/oxygen-scavenging agent
Specification
Physical Attributes- White crystalline powder (sodium sulfite; Na2SO3)
- CAS RN 7757-83-7
- Prone to oxidation (to sulfate) if exposed to air/moisture over time
Compositional Metrics- Codex INS: 221 (sodium sulfite; grouped under 'SULFITES')
- JECFA group ADI for sulfur dioxide and sulfites (expressed as SO2): 0–0.7 mg/kg bw
Grades- Food grade (buyer may reference FAO/WHO JECFA specifications and/or Codex context for sulfites group provisions)
- Industrial/technical grade (fit-for-purpose specifications depend on downstream industrial use)
Packaging- Moisture-protective packaging (e.g., lined bags/drums) to limit caking and oxidation during storage and transit
Supply Chain
Value Chain- Inorganic chemical production → crystallization/drying → quality testing (assay/impurities, grade-dependent) → packaging → distributor/importer → food manufacturer or industrial end user
Temperature- Ambient handling is typical; moisture control is more critical than temperature control for maintaining flowability and assay
Atmosphere Control- Limit exposure to humid air to reduce caking and oxidation during storage and transport
Shelf Life- Shelf-life is mainly driven by packaging integrity and storage humidity; oxidation can reduce effective sulfite content
Freight IntensityMedium
Transport ModeMultimodal
Risks
Regulatory Compliance HighMisuse of sodium sulfite in prohibited food applications (e.g., on fruits/vegetables sold or served raw/fresh) or failure to meet U.S. sulfite declaration expectations can trigger FDA enforcement actions (including import detention/refusal, recalls, and customer program delisting).Lock down intended-use checks against FDA limitations for sodium sulfite; implement finished-product sulfite monitoring where relevant; and align labeling/ingredient declarations with FDA requirements and import enforcement guidance before shipment.
Food Safety MediumSulfites can cause allergic-type reactions in susceptible individuals; undeclared or unexpectedly high sulfite residues can create acute consumer safety and recall risk in the U.S. market.Use supplier qualification + COA review, control dosing, and validate sulfite levels in finished foods (especially where the 10 ppm detectability/labeling threshold is relevant).
Logistics MediumMoisture ingress and oxidation during storage/transport can degrade functional sulfite content and cause caking, increasing out-of-spec risk and downstream processing issues.Specify moisture-barrier packaging, validate warehouse humidity controls, and use first-in/first-out inventory management with re-test protocols for aging lots.
Sustainability- Chemical manufacturing environmental compliance (air emissions and wastewater controls) can affect operating continuity and cost structure for upstream suppliers serving the U.S. market.
Labor & Social- Worker health and safety controls for chemical dust/exposure and safe handling documentation (SDS) are central expectations in U.S. workplace compliance contexts.
FAQ
Is sodium sulfite permitted for use in foods in the United States, and what key restrictions apply?Yes. In U.S. FDA regulations, sodium sulfite is listed as generally recognized as safe (GRAS) when used in accordance with good manufacturing practice, but it has specific prohibitions—such as not being used in meats, not being used in foods recognized as a source of vitamin B1, and not being used on fruits or vegetables intended to be served or sold raw/fresh to consumers.
When do sulfites need to be declared on U.S. food labels?U.S. rules and FDA enforcement guidance emphasize sulfite declaration when sulfiting agents are present in foods in ways that trigger labeling requirements; for standardized foods, FDA regulations define a detectable amount as 10 ppm or more of sulfite and treat non-declaration as misbranding in that context. FDA import enforcement guidance also describes common scenarios and expectations for declaring sulfiting agents in ingredient statements.
If importing food-grade sodium sulfite into the United States, what are common compliance steps before and at entry?If the shipment is regulated as food/food additive, FDA generally requires Prior Notice before arrival, and entry must be filed through CBP processes (entry/entry summary). Operationally, buyers and regulators commonly expect grade-appropriate documentation such as a Certificate of Analysis and a Safety Data Sheet for chemical hazard communication.