31st ICUMSA Session 2018

Final Recommendations

Tim Thys (The Netherlands)

1. It is recommended to extend the field of application of Method GS1-24: “The Determination of Insoluble Solids Content in Raw Sugar” to products covered by GS3 and GS9. Furthermore, the method should be validated, e.g. for the suitability of the filter paper (Whatman 50). Finally, the method should be collaboratively tested.

2. Method GS1-20 (2005) “The Determination of Fine Grain in Raw Sugar by the BSES Method” should be renamed (replacing “fine grain” & “BSES”) and validated.

3. In order to get rid of lead acetate clarification in Method GS 1/2/3/9-1 (2011) “Polarisation of Raw Sugar by Polarimetry – Official”, it is recommended to study alternative clarifying agents (e.g. Carrez I & II). A validation study should also quantify effects of other optically active components (fructose / dextran). Finally, the method should be collaboratively tested.

Referee: Karen Pardoe (UK)

1. GS2 Referee to update GS2/1/7/9-33 with respect to the rosaniline reagent required; the specific chemical(s) that are suitable and stability thereof.

2. GS2 Referee to update GS2/1/7/9-33 with respect to the suitability of sucrose for use as a reagent.

3. GS2 Referee to update GS2/1/7/9-33 with respect to the use of sodium sulphite as anhydrous and heptahydrate forms.

4. GS2 Referee to update GS2/1/7/9-33 with respect to details of reagents; information about preparation and reference to suitable commercially available reagents.

5. GS2 Referee to obtain details of methods in use for the determination of sulphite in sugar that are in routine use but not one of the available ICUMSA Methods.

6. GS2 Referee to define a collaborative study of the most commonly used methods for the determination of sulphite in white sugar, based on the completion of Recommendations 1 to 5.

7. GS2 Referee to propose change to SUPSMICRO scheme description so that it includes the relevant ICUMSA Method references.

8. GS2 Referee to provide SUPS with information about test materials relevant to obtaining data relevant to precision data for ICUMSA Methods.

GENERAL SUBJECT 3 Speciality Sugars
Referee: Andreas Georg Degenhardt (Germany)

1. The status of ICUMSA Method GS3-51 (2017) “The Determination of Sulphite as Sulphur Dioxide” (SO2) in Brown Sugars by the Optimized Monier-Williams Method combined with Titration as well as the status of ICUMSA Method GS3-52 (2017) The Determination of Sulphite as Sulphur Dioxide (SO2) in Brown Sugars by the Optimized Monier-Williams Method combined with High-Performance Ion Chromatography (HPIC) should be changed from “Tentative” to “Accepted”.

2. Analytical methods should be assed for applicability towards the determination of glucose, fructose, sucrose, maltose and sodium in burnt sugar syrups and caramel syrups. The referee should give an overview with an appraisement.

Referee: Camille Roussel (Reunion/France)

1. Continue the re-writing of disintegration method collaboratively with associate referees and ICUMSA Board

2. Write a press method based on the following recommendations:

It is recommended to adopt a sorption water value to 25%dry fibre

It is recommended to assume equivalence in the different juice composition (undiluted, extracted and residual)

Given that Berding’s computation is based on physical and not theoretical products (plug and juice) and that the drying of plug cake is more rapid and convenient than the cane drying, it is recommended that press computation should be based on Berding’s Method.

Referee: Dierk Martin (Germany)

1. Method GS6-8 (2017) shall be completed with precision data elaborated in the collaborative study 2017. Moreover, a remark shall be added concerning the choice of a suitable dilution factor in order to achieve lower limits of determination.

2. The “Tentative” status of Method GS6-8 (2017) “The Determination of Glucose Content in Sugar Beet by an Immobilized Enzyme Biosensor Method” should be replaced by “Official”.

3. Developments of methods for the determination of further parameters which might be relevant for the description of sugar beet quality should be observed.

GENERAL SUBJECT 9 Plantation and Mill White Sugar
Referee: Vasudha Shirish Keskar (India)

1. Method GS 9/1/2/3-8 (2011) “The Determination of Sugar Solution Colour at pH 7.0 by MOPS buffer method” is to be redrafted with inclusion of changes making it applicable for all products.

2. Method “Elemental analysis of plantation white sugar using ICP-MS” should be given tentative status on conditional basis until further work on the extension of Method GS2-51 for inclusion of plantation white sugars is carried out. Note about this conditional status to be included in the content of the method.

SUBJECT 1 Constitution and By-Laws
Referee: Geoff Parkin (UK)

1. The title of Subject 1 should be changed from “Constitution and By‐Laws” to “Articles of Association and By‐Laws”

SUBJECT 2 Method Format, Collaborative Testing and Statistical Treatment of Data
Referee: Roger Wood (UK)

1. To ask and encourage members of ICUMSA to post general over-arching information on the ICUMSA Website and to discuss/agree on how such information could be effectively discussed.

SUBJECT 3 Colour, Turbidity and Reflectance Measurement
Referee: Christiane Lakenbrink (Germany)

1. It is recommended to finalize the project FV 42029 with the PTB.

2. It is recommended to study the influence of different qualities of the MOPS reagent on the measured colour in solution. The study needs the support from other referees with
regard to sugar samples and MOPS reagents from different suppliers.

SUBJECT 5 Chemical Method
Referee: Maciej Woitczak (Poland)

1. Following the recommendations 2 & 3 from the last Session, Method GS2/1/7/9-33 should be rewritten for white sugar and plantation white sugar and Method GS4/7/8/5-2 should be rewritten for molasses and beet sugar processing.

2. Depending on the General Subjects needs the Method GS4/7/3-12 “Determination of Moisture by Karl Fisher Method” should be further investigated and extended to new fields of application, particularly for GS1, GS2, GS3 and GS9 by organizing collaborative studies on it.

3. Further investigations of dextran analysis methods should be conducted in cooperation with GS8.

4. The collaborative study of the Method GS2/4/8-54 “Determination of non-ionic surfactants in white sugar, molasses and dried beet pulp” should be organized in cooperation with GS2, GS4 and GS8.

SUBJECT 6 Microbiology
Referee: Maritta Jacobs (Germany)

1. ICUMSA Method GS2/3-50 (2017) “The Determination of Thermophilic Acidophilic Bacteria (TAB) and Guaiacol producing TAB (GP-TAB) in Sugar Products – Accepted”:
The method will be extended by techniques describing the analysis of non-easily filterable samples and the analysis of dark syrup samples present/absent test).

2. Method GS2/3-52 (2017) “The Determination of beta-glucuronidase-positive Escherichia coli and alpha-galactosidase-positive coliform bacteria in Sugar and Sugar Products by the Membrane Filtration Method – Tentative” has been extended by further chromogenic agar and nutrient pads. The status should be changed to “Accepted”.

3. Method GS2/3-53 (2017) “The Determination of Osmotolerant Yeasts and Xerophilic Moulds in Sugar Products by the Membrane Filtration Method or the Pour Plate Method – Tentative” will be extended by a second incubation temperature, 25 °C and 30 °C and an incubation time of at least 5, preferably 7 days. Further, the medium DG18M will be included. The status should be changed to “Accepted”.

4. Method GS2/3-47 (2015): “The Determination of Yeasts and Moulds in Refined Sugar Products by the Pour Plate Method or the Membrane Filter Method – Official”: It is recommended to incubate samples on two different media e.g. YGC-agar or wort nutrient pads at 25 °C and 30 °C for at least 3, preferably 5 days.

5. Method GS2/3-42 (2002) “Sampling of Refined Sugar Products for Microbiological Analysis – Official”: The method will be extended by introduction of sterile disposable sampling materials.

SUBJECT 8 Sampling and Sample Preparation
Referee: Alan Mead (UK)

1. That the title of Subject 8 be changed from ‘Sampling and Sample Preparation’ to read SUBJECT 8 – Sampling, Sample Handling and Sample Preparation.

2. a) Included within the ICUMSA Method’s Book should be guidance on the collection of primary samples, highlighting known pitfalls and suggesting ways that they may be avoided.

2. b) ICUMSA should limit the recommendations in its Methods Book to the:

– handling of the primary samples

– the mixing of the primary sample(s)

– preparation of the secondary samples

the manner in which the secondary samples are divided into aliquots for the various analyses required.

3. On acceptance of recommendations 1 & 2, and based on sound theories of sampling, initiate investigations to determine how the degree of uncertainty, subsequent to the collection of primary sample(s), can be determined and what that degree is.