Testing for honey fraud

Honey fraud can take on many forms (click here for an overview on the types of honey fraud). This makes testing the authenticity of honey very complex, as there is no single test that can check for all types of honey fraud.

Honey authenticity testing is like a jigsaw puzzle: the more pieces you can collect, the more information you can reveal about a sample.

That said, it’s also important to define what type of honey fraud you are concerned about, to ensure that the correct test method to investigate a sample.

Methods to detect types of honey fraud

Honey adulteration

Honey has a specific sugar profile, and the addition of sugar syrups to honey may alter this profile. Thus, testing the sugar profile of honey is a basic approach to evaluating whether it has been adulterated. This can be determined using various analytical techniques, such as HPLC (High-performance liquid chromatography).

However, fraudsters may add sugar syrups that are tailored to mimic the natural sugar profile of honey to try and avoid the detection of these adulterants. Therefore, additional tests are valuable to determine whether or not a honey has been adulterated.

Stable carbon isotope ratio analysis (SCIRA) is a technique used to confirm the type of plant from which a honey or sugar syrup is made. This method is based on the principle that honey is generally made from the nectar of dicotyledonous (C3) plants, while most sugar syrups are made from monocotyledonous (C4) plants such as corn and cane. SCIRA is usually a ‘go-to’ method for investigating honey adulteration, but it does have some limitations.

Honey adulteration with sugar syrups from C3 plants such as rice and beet cannot be detected by SCIRA, as these syrups have a similar isotope fingerprint to honey. Fraudsters know this; thus there is a risk that they will capitalise on this shortcoming.

Recent studies have highlighted the potential of using oligosaccharides with a high degree of polymerisation as markers of adulteration. Syrups of both C3 and C4 origin generally contain detectable levels of these oligosaccharides, while authentic honey does not. Therefore, testing for oligosaccharides with a high degree of polymerisation is another ‘piece of the puzzle’ that can be used to detect honey adulteration.

Honey mislabelling

Several methods are available for determining the botanical and geographical origin of honey.

Honey origin is traditionally assessed using melissopalynology, which involves the microscopic analysis of pollen present in honey.

It is generally accepted that a honey can be classed as monofloral if 45% or more of its total pollen grains are from a single plant species. However, there are some exceptions to this rule. Pollen is naturally underrepresented in certain plant species, which means that pollen counts will naturally be lower in honey produced using those plants. Examples include honey made from the pollen of citrus, lavender and rosemary blossoms. Honey with this botanical origin may be classed as monofloral if 10-20% of the total pollen grains are from the respective plant species.

Although melissopalynology is an incredibly valuable technique for determining honey origin, it has some drawbacks. Pollen analysis must be conducted by experienced personnel using comprehensive pollen reference databases. It is also a time-intensive technique, with low sample throughput. Therefore, other analytical techniques have been explored for their ability to characterise the botanical origin of honey on a larger scale.

The use of phenolic compounds as chemical fingerprinting markers is an example of an alternative method for distinguishing the botanical origin of honey.

Due to the complexity of origin testing, there is currently no standardised and/or regulated test available that can confirm the botanical source and geographical origin of honey.

Misrepresentation of honey quality

Different physico-chemical tests are used to investigate honey quality, by measuring certain parameters that relate to particular characteristics.

HMF content and diastase activity are valuable parameters used to assess the quality and freshness of honey. HMF (hydroxymethylfurfural) is an intermediate product of the Maillard reaction that is not naturally present in honey, but forms when honey is thermally processed or stored for prolonged periods. Diastase activity is a measure of the enzymes naturally present in honey that catalyse the breakdown of starch into maltose. The diastase activity of honey decreases as a consequence of thermal processing or the long-term storage of honey.

Moisture content is another parameter used to assess honey quality. High moisture content may indicate that honey has been harvested too early, which ultimately affects its shelf life. Honey with high moisture content may ferment, spoil or lose flavour more quickly.

FACTS honey test package

FACTS offers a honey test package that evaluates honey quality and checks for the presence of honey adulterants.

This package includes various parameters selected from the Regulations Relating to the Grading, Packing and Marking of Honey and Mixtures of Bee Products intended for sale in the Republic of South Africa (R. 835) that have been deemed most relevant to assessing honey composition, quality and ripeness, and which enable robust honey fraud detection.

R. 835 lists 17 parameters for measuring honey authenticity, and states that any of the relevant tests may be selected to profile an authentic honey product. There is some redundancy between the 17 parameters listed. Therefore, FACTS has identified a combination of parameters that will provide a holistic overview of the authenticity of a honey sample, while minimising testing costs.

The following parameters are included in the FACTS honey authenticity test package:

FACTS strives to stay on top of honey-fraud trends and come up with testing solutions that best support our clients’ needs. For more information on honey testing, assistance with food fraud, and/or consulting on regulatory requirements, please contact us.

Other articles and resources you may be interested in:
Honey Fraud
Honey Variations
Types of honey products
Video | Combatting Honey Fraud
Tesco’s house-brand honey suspected of adulteration