CAS number, E number and INS number: what buyers should check
This practical article helps food-additive buyers compare chemical, regulatory and commercial identifiers across supplier specifications, certificates of analysis, labels and shipping documents.
Application context
Food additives may be described by several identifiers at the same time. A supplier specification may list a chemical name and CAS number, while a regulatory declaration or product label may use an E number, INS number or permitted additive name.
These identifiers serve different purposes and should not be treated as simple substitutes for one another. Buyers should check them together with the product form, chemical composition, hydration state, concentration, carrier system, purity and intended food use.
A correct identifier does not by itself confirm that the offered material is the correct commercial grade. Two products can share a general additive name while differing in assay, particle size, physical form, carrier content, manufacturing origin or application performance.
Understanding the main identifier types
CAS number
A CAS number is a numerical identifier associated with a particular chemical substance. It is commonly shown on specifications, safety data sheets, technical documents and customs-related records.
Buyers should confirm that the CAS number corresponds to the exact chemical form being purchased. Anhydrous, hydrated, salt or solution forms may have different identities or specifications even when their commercial names appear similar.
E number
An E number is used for food additives authorised within the relevant European regulatory framework. It can appear in specifications, regulatory statements and finished-product ingredient declarations.
The presence of an E number does not mean that the additive is permitted without restriction in every food category. Use may depend on the product category, technological function, maximum level and other regulatory conditions.
INS number
An INS number belongs to the International Numbering System for Food Additives. It provides a common numerical reference used in international food-additive discussions and documentation.
An INS number may resemble a corresponding E number, but buyers should still verify the applicable national or regional rules for the destination market. Numbering alone does not replace a market-specific regulatory review.
Matching identifiers across documents
Product identity should be consistent across the supplier's technical and commercial documentation. Buyers commonly compare:
- Commercial product name and grade.
- Chemical or generic food-additive name.
- CAS number where applicable.
- E number and INS number where applicable.
- Chemical formula or molecular description.
- Anhydrous, monohydrate, dihydrate or other physical form.
- Purity, assay or active concentration.
- Carrier or standardising ingredient in blended products.
- Country of origin and manufacturing site.
- Lot number and document revision.
The same product description should be traceable through the specification, certificate of analysis, safety data sheet, allergen statement, product label, packing list and invoice. Small wording differences may be acceptable, but unexplained differences in identity or grade should be clarified.
Key buyer checks
- Confirm the complete product name rather than relying on a number alone.
- Check whether the identifier applies to the exact chemical form offered.
- Verify whether the material is pure, standardised, diluted or blended with a carrier.
- Compare the CAS, E and INS references across all current supplier documents.
- Confirm the required food grade, purity standard and applicable compendial reference where relevant.
- Review the intended technological function and target food category.
- Check permitted-use conditions in the destination market rather than assuming that approval in one market applies globally.
- Confirm the required finished-product label declaration with the customer's regulatory or labelling team.
- Review whether alternative names, synonyms or spelling variations refer to the same substance.
- Ensure that internal purchasing systems use a clear product code linked to the approved specification.
Managing discrepancies
A difference between documents does not always mean that the material is wrong, but it should be investigated before approval. Common causes include outdated specifications, typographical errors, alternative synonyms, differences between hydrated and anhydrous forms, or distributor documents that use a shortened name.
Buyers should request written clarification where an identifier is missing, inconsistent or linked to an unexpected product form. The supplier may need to issue a corrected specification, revised certificate or formal identity statement.
If the physical shipment label does not match the approved product name or lot documentation, the material should be handled according to the buyer's hold and nonconformance procedure until the identity is confirmed.
Any approved change to the product identity, grade or regulatory status should be controlled through the supplier's change-notification process and the buyer's internal specification review.
Documents and quality checks
Before confirming an order, buyers commonly review a current product specification or technical data sheet, certificate of analysis, safety data sheet where applicable, origin information, shelf-life statement, storage conditions, label details and packing information.
Documents useful for identifier verification may include:
- Current product specification.
- Batch-specific certificate of analysis.
- Safety data sheet where applicable.
- Regulatory or food-grade compliance statement.
- Composition statement for blends and preparations.
- Country-of-origin and manufacturing-origin declaration.
- Allergen, GMO and animal-origin statements.
- Halal, kosher, organic or other certification documents.
- Product label or bag-marking example.
- Change-control and document-revision information.
Buyers should confirm that all documents refer to the same product grade and are within their stated validity period. An old safety data sheet or specification may contain identifiers that have since been corrected or updated.
Related quality and procurement topics
This topic is connected to Quality & Procurement. Identifier review forms part of a wider product-approval process involving specifications, traceability, regulatory checks and supplier-document control.
Related areas for review include:
- Certificate-of-analysis verification.
- Approved supplier and product lists.
- Specification and revision control.
- Label and ingredient-declaration review.
- Country-of-origin and customs documentation.
- Supplier change-notification procedures.
How to turn this topic into an inquiry
Send the article title, product name, chemical form, required CAS number, E number or INS number, target specification, quantity, destination country, packaging preference, required declarations and shipment timing.
If you have a current supplier specification, certificate of analysis, safety data sheet or product label, include the relevant identifiers so the offered material can be compared more accurately.