33rd ICUMSA Session 2023

Final Recommendations


Referee: Tim Thys (the Netherlands)


  1. Remove Method GS1-24 (2017) The Determination of Insoluble Solids in Raw Sugar by Depth-Type Filtration – Tentative from the Methods book.
  2. The Brazilian NC shall be contacted again so that the work on the particle size distribution method performance can be progressed.
  3. All GS1 methods to be revised (relative to the list provided by the General Secretary).
  4. Further investigation into the use of clarification alternatives to lead acetate and whether alternatives can be included in method GS1‐1 is required.
    Additional investigations should be separately carried out using no clarification agent at all and only applying celite as a filter aid combined with pressure / gravity filtration.
    The current phrasing “approximately 3.5 g Celite” as filter aid should be more specified in the next revision of method GS1-2.
    Referring to the LGC SUPS data in the Appendix, where column ‘secondary method’ mentions ‘other’, it would be valuable to obtain more information on those “other” methods by asking LGC to approach the participating labs.
  5. Further testing on GS1-16 and GS1-17 should be planned to evaluate for efficient use in trade analysis.


Referee:  Carol Wambolt (USA)           Presented by Karen Pardoe


  1. The work to finalise the details for determination of sulphite in white sugar by an iodometric method shall be continued.
  2. A draft method, based on Recommendation 1, shall be produced for commenting from Associate Referees and Subject 5 Referee.
  3. A collaborative study for the draft method of Recommendation 2 shall be organised.

GENERAL SUBJECT 3 – Speciality Sugars

Referee:  Andreas Georg Degenhardt (Germany)


  1. The draft method in Annex II to the present Report was successfully submitted to a collaborative study. It shall be officially adopted and included into the ICUMSA® Methods Book. The Method title is: Method GS3-31 (2024): 5-Hydroxymethylfurfural (HMF) in Sugar Syrups and Invert Sugar Syrups by High Performance Liquid Chromatography (HPLC) – Official.
  2. A method for determining the insoluble residues in the speciality sugar products Demerara and Muscovado should be developed. When this has been done, an international collaborative study shall be performed to determine the insoluble levels.
  3. Under the guidance of GS3 and with the help of GS1, the applicability of ICUMSA® Method GS1/3-7 (2011) for the brown sugar specialties Demerara and Muscovado shall be verified. – GS3, in collaboration with GS1, shall organise an international collaborative study to validate the parameter colour in solution in dark Demerara as well as Muscovado specialities, incl. Plantation White sugar (PWS), to collect repeatability and reproducibility performance data.


Referee: Sebastiaan van Berchum (The Netherlands)


  1. Start a collaborative study on the use of both Carrez solutions and Octapol as clarifiers in the determination of the calculated polarimetric sucrose content of molasses, with the aim to find an alternative for lead acetate clarification in Method GS 4/7-1 (2013).
    The study should include both beet and cane molasses.

General Subject 5 – Cane

Referee:  Mathilde Mellin (France)


  1. The Precision paragraph of GS5-2 should be completed with data given above and summarized in Annex A.
  2. Following successful single laboratory validation of Method GS5-2 its status should be changed from Tentative to Official.
  3. On acceptance of Recommendation 2, it is recommended that Method GS5-2 becomes the Official (Reference) Method and (Reference) is removed from GS5-1.


Referee: D. Martin (Germany)


  1. Method GS6-3 (1994) Polarisation of Sugar Beet by the Macerator or Cold Aqueous Digestion Method using Aluminium Sulphate as Clarifying Agent – Official should be replaced in the ICUMSA® Methods Book with the revised 2024 version.
  2. Method GS6-5 (2007) α-Amino Nitrogen in Sugar Beet by the Copper Method (‘Blue Number’) – After Defecation with Basic Lead Acetate – Official – After Defecation with Aluminium Sulphate – Official should be replaced in the ICUMSA® Methods Book with the revised 2024 version.
  3. Method GS6-7 (2007) Potassium and Sodium in Sugar Beet by Flame Photometry – Official should be replaced in the ICUMSA® Methods Book with the revised 2024 version.
  4. Sampling procedures for sugar beet and preparation of beet brei should be described and published as an ICUMSA® Specification and Standard.

GENERAL SUBJECT 7 – Cane Processing

Referee: G. Eggleston (USA)


  1. Accept as an ICUMSA GS7 (2024) Tentative Method “Total, Soluble, and Insoluble Starch in Cane Raw Sugars by Microwave-Assisted Neutralisation – Tentative”, following acceptable single laboratory validation results.
  2. Conduct an Inter-Laboratory analysis test of the method “Total, Soluble and Insoluble Starch in Cane Raw Sugars by Microwave-Assisted Neutralisation”.

GENERAL SUBJECT 8 – Beet Processing

Referee: Florian Emerstorfer (Austria)


  1. Further improve, collaboratively test and validate Method GS 8-19 (2009) “The determination of dextran in beet raw juice and thick juice by a modified alcohol haze method – Tentative” with the focus on raw juice.
  2. The DASA and HPAEC-PAD method for dextran analysis are not suitable for different reasons and are thus not going to be taken further within ICUMSA GS8.
  3. Further monitor developments in the field of antibody test-kits for dextran determination.
  4. Discuss at the upcoming session if the determination of the dextran hydrolysing activity of (commercial) dextranase products should be taken further within ICUMSA GS8.

General Subject 9 – Plantation White Sugar

Referee: Vasudha S. Keskar (India)


  1. A collaborative study should be initiated with higher sulfite containing plantation white sugar samples (up to 50 mg/kg) so that the field of application of Method GS2-33 (2022) „Sulfite in white sugar by the Rosanilin colorimetric method“ can be extended to include Plantation White Sugar.
  2. The alternative method for GS2/3/9-19 should be collaboratively tested for Plantation White Sugar (GS9) and Speciality Sugars (GS3). The work will be done in association of Referee GS3.

SUBJECT 1 – Articles of Association and By-Laws

Referee: M. Leijdekkers (Netherlands)


  1. The proposed scope of the ICUMSA® Methods Book shall be presented to the Executive Committee and, after adoption, be published on the ICUMSA® website.
  2. A special resolution shall be proposed at the Executive Committee meeting to adopt the amended Articles of Association and By-Laws. After adoption by the required majority of votes, the amended Articles of Association and By-Laws shall be registered at Companies House.

SUBJECT 2 – Method Format, Collaborative Testing and Statistical Treatment of Data

Referee: Hanjo Puke (Germany)


  1. The pending Recommendations listed in Table 1 shall be continued until they have been resolved.
  2. Ad Recommendation 5 (2002): The results of the 1998 collaborative study cannot be retrieved. The Method has been sold only three times in the last 20 years, the last time in 2011. Total usage is certainly unknown (Methods Book owners). These are only the sales as single Method. Because of the limited interest in the Accepted Method GS8/2/3/4-9 (2000) the following Recommendation is proposed:
    Method GS8/2/3/4-9 (2000) shall be withdrawn from the ICUMSA® Methods Book.
  3. Ad Recommendation 6 (2002): Method GS2/3-35 (2000) “The Determination of Sulphite in Refined Sugar Products excepting Brown Sugars by an Enzymatic Method – Official – The Determination of Sulphite in Brown Sugars – Tentative”. The applicability of the method is Tentative for Brown Sugars since 1995. Attempts to upgrade it to Official were not successful.
    The applicability of Method GS2/3-35 (2000) to Brown Sugars shall be withdrawn.
  4. The updated Rules and Responsibilities for ICUMSA® Referees (2023) as reproduced in Annex 1 shall replace the 2021 version on the ICUMSA® Website.
  5. The new Guidelines and Tools for ICUMSA® Referees (2023) as given in Annex 2 shall be added to the members’ section of the ICUMSA® Website.
  6. The term “Polarisation” shall be replaced by the term “Polarimetric sucrose content in ICUMSA® SPS-1 and all ICUMSA® Methods, where it appears. The definition of “Polari-metric sucrose content” shall be added to the definitions on the ICUMSA® Website.
  7. The new symbol CIU shall be used for the ICUMSA® Colour in solution measured in ICUMSA Units (IU).

SUBJECT 3 – Colour, Turbidity and Reflectance Measurement

Referee: C. Lakenbrink (Germany)


  1. The current version of ICUMSA® Method GS1/3-7 (2011) shall be replaced by the revised version Method GS1/3-7 (2024) (see Annex 1) in the ICUMSA® Method Book.
  2. The current version of ICUMSA® Method GS2/3-9 (2005) shall be replaced by the revised version Method GS2/3-9 (2024) (see Annex 2) in the ICUMSA® Method Book.
  3. The current version of ICUMSA® Method GS2/3-10 (2011) shall be replaced by the revised version Method GS2/3-10 (2024) (see Annex 3) in the ICUMSA® Method Book.
  4. Further collaborative testing should be carried out to investigate the influence of vacuum filtration compared to pressure filtration for the defined scope of the method before replacing the current version of ICUMSA® Method GS9/1/2/3-8 (2011) with the revised version Method GS9/1/2/3-8 (2024) (see Annex 4) in the ICUMSA® Method Book
  5. The current version of ICUMSA® Method GS2-11 (2007) shall be replaced by the revised version Method GS2-11 (2024) (see Annex 5) in the ICUMSA® Method Book.
  6. The current version of ICUMSA® Method GS2-13 (2017) shall be replaced by the revised version Method GS2-13 (2024) (see Annex 6) in the ICUMSA® Method Book.

Subject 4 – Physical Methods

Referee: Mathis Kuchejda (Germany)


  1. Apply a new definition of “Normal Sample Solution” in Method GS2/3-1 §§ 3.1 and 6.2 and in Method GS1/2/9-1 § 3.1 after it is developed along with the revision of SPS-1.
  2. Simplify GS2-1 by replacing the volumetric preparation and subsequent volume correction with the gravimetric preparation.
  3. Evaluate the applicability of the gravimetric preparation for impure sugars by measurement of the density of “normal sugar solutions” prepared with plantation white sugar (GS9) and raw sugar (GS1).
  4. The S4 Referee to contact pharmacopeia (USP and EP) and request that chapters 781, 831 and 841 are harmonized with respect to 20 °C being defined as the reference and measuring temperatures. It is also recommended to change reference temperatures within the monographs in all three applications to 20 °C.
  5. Evaluate the scope of the NIST study for the application in polarimetry, refractometry and density.

Subject 6 – Microbiological Methods

Referee: M. Klingeberg (Germany)


  1. The new format rewrite of ICUMSA@ Method GS2/3-50 should be published as GS2-50 (2024) Thermophilic Acidophilic Bacteria (TAB) and Guaiacol Producing TAB (GP-TAB) in White Sugar – Accepted.
  2. The new format rewrite of ICUMSA® Method GS2/3-41 should be published as GS2-41 (2024) Total Mesophilic Aerobic Microorganisms in White Sugar by Membrane Filtration or Pour Plating – Accepted.
  3. The modified and new format rewrite of ICUMSA® Method GS2/3-49 should be published as GS2-49 (2024) Thermophilic Spore-Forming Bacteria in White Sugar by Membrane Filtration or the Pour Plating – Accepted.
  4. The update and new format rewrite of ICUMSA® SPS12 should be published as Specification and Standard SPS-12 (2024) Sampling of Crystalline, Paste and Liquid Sugars for Microbiological Analyses.
  5. The terms (sugar, sugar products, dark syrup, refined sugar products) in the texts of all microbiological methods shall be defined as soon as possible in accordance with the definitions of ICUMSA® in general.

SUBJECT 7 – Sampling, Sample Handling and Sample Preparation

Referee: Alan N. Mead (United Kingdom)


  1. The membership of ICUMSA®, guided by the Subject Referees for GS2, GS3 and GS9, should decide if a further study to quantify the errors attributable to Sample Handling and Sample Preparation is warranted.
  2. If Recommendation 1. is accepted, then a sub-committee should be formed, comprising those with the necessary skills and access to suitable facilities, to carry out the study.
  3. In conjunction with the GS5 Referee, the procedure for cane preparation be written for inclusion in Standards & Specifications in a similar manner to that of beet.