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This study (open access) used machine learning classification models to identify monosaccharide markers for coffee adulteration.  These markers (proposed thresholds for glucose, xylose and mannitol) are suitable for authenticity monitoring vs Brazilian official regulatory standards (SDA Ordinance 570) using High-Performance Anion Exchange Chromatography with Pulsed Amperometric Detection and can flag adulteration with corn, wheat, and barley adulteration from 3%.

The training and validation sets were prepared from verified samples supplied by the Brazilian Ministry of Agriculture and roasted, ground and adulterated in-house.  Coffees (157 raw samples) comprised of arabica and canephora species from eight different states.  Adulterants were acai, husk, barley, wood fragments, corn and wheat ranging from 1 – 20%.

Photo by Nathan Dumlao on Unsplash

The European Commission’s Joint Research Centre (JRC) have recently produced “authentic” and “inauthentic” honey reference materials.  These materials will shortly be available within laboratory proficiency testing (PT) schemes.  Analysis of reference materials (where a laboratory’s result can be compared to a traceable known value) and participation in PT schemes (where laboratories compare their own results to those of their peers testing the same sample) are critical aspects of the Quality Assurance system of any testing laboratory, and are mandatory where testing is accredited to ISO 17025.

Participants in LGC AXIO’s Food Chemistry proficiency test for honey parameters will have the option to take part in an additional exercise in the June 2026 round. This add‑on focuses on the analysis of honey authenticity.  Alongside the standard honey sample, laboratories may choose to analyse two extra honey samples supplied by the JRC.  These materials are intended to support the interpretative assessment of sugars commonly used as authenticity markers.

The two supplementary honey test materials are intended for:

• Sucrose analysis
• Fructose analysis
• Glucose analysis

Participants will also be asked to provide an authenticity assessment for each sample, including whether it meets the laboratory’s own criteria and the basis for that judgement.

 Laboratories that would like to receive the additional honey samples should contact axiopt@LGCGroup.com 

 LGC AXIO are a partner of FAN and we continue to be grateful for their support alongside all our partners.

Photo by With Mahdy on Unsplash

There is no single definitive test for dilution of honey with foreign sugar syrups.  An untargeted test, often used to contribute to an analytical weight of evidence, is proton NMR followed by chemometric pattern recognition based on variations in the sugars profile.  One disadvantage of this technique is a lack of sensitivity. 

LCMS is a more sensitive technique and could – in principle – be used in a similar untargeted manner to drive pattern recognition statistics based on the sugar profiles of a database of reference honeys.  The limiting factor has been the computing power that would be needed to “re-set” the database each time a new chromatographic peak is measured or data from different chromatographic systems are combined. (this is why untargeted LCMS is often used in authenticity testing as a 1-off development tool to identify marker compounds, which are then used as the basis for a more routine targeted test, rather than being used as a routine untargeted test).

In this paper (open access), the authors resolved the computing power limitation by using their Bucketing of Untargeted LC-MS Spectra (BOULS) data processing approach which they have previously published.  They demonstrated that untargeted LCMS testing (combining data from different systems, HILIC column with MS in both positive and negative ionisation mode) could discriminate a range of adulterated honeys (rice, beet and high-fructose corn syrups added at 5% to a reference set of 34 North German honeys) from their unadulterated counterparts.

As is the case with all untargeted analytical techniques, the key to using this method routinely would be building a robust reference database of verified authentic honeys that is fully representative of all types and origins on the market.

Photo by Roberta Sorge on Unsplash