Regulatory framework, analytical authentication and certified fungal origin

Why chitosan origin is a critical issue in oenology

Chitosan is today widely recognised as a valuable tool in modern winemaking, notably for the control of spoilage microorganisms and as part of strategies aiming to reduce sulfur dioxide use. However, beyond its functional properties, the origin of chitosan is a decisive criterion that directly impacts regulatory compliance, product safety, and consumer protection.

In oenology, chitosan is not considered a generic additive. Its use is strictly regulated by the International Organisation of Vine and Wine, which defines both the authorised sources of chitosan and the analytical criteria required to demonstrate its compliance with the International Oenological Codex.

As a result, chitosan origin cannot rely on declarations alone. It must be scientifically demonstrated, using methods explicitly admitted by OIV resolutions. This requirement is essential to ensure that only authorised chitosan sources are used in winemaking and that wine consumers are fully protected.

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Chitosan: definition and use in winemaking

Chitosan, a natural biopolymer derived from chitin, which is a natural polysaccharide. It has emerged as a versatile and sustainable tool in modern winemaking. Its unique chemical properties and broad spectrum of applications make it a valuable alternative to traditional additives such as sulfur dioxide.  

Different origins of chitosan and their implications

Traditionally, chitosan comes from animal sources such as shellfish waste (shrimp, crabs), which raises concerns about allergy risks, quality variability, and traceability—making it difficult to guarantee the highest safety standards for consumers. 

In parallel, chitosan and chitin-glucan from fungal origin have been developed. Thanks to its non-animal origin, these functional biopolymers open a range of opportunities for industries without any risk of allergenicity, relying on quality and traceability. 

For these reasons, the OIV has retained only two safe fungal sources of chitosan for wine industry: Aspergillus niger and Agaricus bisporus. 

OIV Referencing Steps for Chitosan 

A new  method to reinforce the determination of fungal origin : the Stable Isotope Ratio (SIR) method

To verify the origin of chitosan used in oenological products and protect wine consumers’ health, a new method called Stable Isotope Ratio (SIR) method, defined in Resolution OIV-OENO 728-2025, provides another reliable way to confirm fungal origin. This analysis distinguishes sources through δ¹³C and δ¹⁵N values, ensuring authenticity and excluding any animal origin, not authorized. 

The SIR method has been developed by Fondazione Edmund Mach. Some renowned labs such as Eurofins have taken part to the validation of this method. It complements other parameters defined in the original chitosan monograph (% residual glucans, settled density, viscosity) to eliminate any doubt about origin. Additionally, two complementary methods (thermogravimetric analysis and FTIR coupled with chemometrics), published by Claverie et al. (2013), systematically confirm the SIR results. 

How to ensure fungal origin of chitosan

4 characteristics guarantee compliance with the OIV International Oenological Codex for pure chitosan: 

Three characteristics from Resolution OIV-OENO 368/2009:  

One characteristic from Resolution OIV-OENO 728-2025:  

These criteria guarantee fungal chitosan origin from Aspergillus niger or Agaricus bisporus, excluding any animal origin, not admitted by the OIV.