Manuka Honey Authentication
The Honey (England) Regulations 2015 and the EU Honey Directive specify that a honey to be labelled as having a specific floral original it must be wholly or predominantly derived from that floral source and have corresponding microscopic, physical, chemical and sensory characteristics (Codex Alimentarius Commission, 2001). Therefore, for a honey to be truly labelled as manuka honey it must come wholly or predominantly from manuka (Leptospermum scoparium) nectar. Manuka (Leptospermum scoparium) honey contains unique and beneficial compounds, laboratory testing for these compounds is used to determine the purity and potency of manuka honey.
In New Zealand the Ministry for Primary Industries (MPI) enforces a scientific regulatory definition for exported manuka honey based on chemical fingerprinting and pollen DNA marker analysis (Burns 2018, McDonald 2018, Ministry for Primary Industries 2017). The definition requires minimum amounts of four specific phenolic compounds to be present in the honey:
- 2-methoxybenzoic acid
- 3-phenyllactic acid
- 4-hydroxyphenyllactic acid
- along with a manuka pollen DNA marker.
These compounds are produced naturally in the nectar of manuka flowers and therefore naturally occur in manuka honey (Smallfield 2018).
In addition to the compounds specified by the MPI definition, Comvita scientists, and others, have pioneered the discovery of other compounds unique to manuka honey including dihydroxyacetone (DHA), methylglyoxal (MGO), leptosperin and lepteridine which are used to authenticate the purity and potency of manuka honey (Bong 2017, Bong 2018, Daniels 2016, Kato 2014, Lin 2017, Stephens 2017)
Unique Compounds In Manuka Honey
DHA is a compound found in the nectar of manuka flowers, high levels of DHA in nectar converts over time in manuka honey to MGO (Adams 2009)
MGO is the bioactive compound found in manuka honey responsible for its unique non-peroxide antibacterial activity (Adams 2008, Mavric 2008). However, in some food fraud cases synthetic MGO has been added to honey to create ‘fake’ manuka honey, because of this measuring MGO alone does not give consumers enough assurance of the purity and quality of manuka honey. The presence and levels of other unique compounds, in addition to MGO, is needed to verify that manuka honey is genuine.
Leptosperin is a key unique compound found only in manuka honey, it is extremely difficult to make synthetically and is not commercially available so it c annot be artificially added to manuka honey. The presence of leptosperin at specific levels in manuka honey provides assurance to consumers that the honey is authentic manuka honey with a natural manuka MGO source. Comvita routinely measures leptosperin levels to verify both the floral source and to cross-check the potency corresponding to each UMF grade and as a counter-fraud measure. [we could insert the graphic from the main manuka page showing how the lepto/mgo/dha move across each grade]
Lepteridine is another unique manuka nectar-derived compound discovered by Comvita Scientists (Daniels 2016). As with leptosperin, lepteridine is difficult to make synthetically and is not commercially available so it cannot be artificially added to honey making it’s presence in manuka honey a good indicator of authenticity.
Unique Manuka Factor (UMF™)
The Unique Manuka Factor (UMF™) is an independently certified quality assurance mark for genuine New Zealand monofloral manuka honey. All UMF certified products must first meet the MPI definition of monofloral manuka honey, UMF™ provides additional assurance to consumers. UMF™ measures both the purity and quality of manuka honey based on the levels of three unique signature compounds: leptosperin, dihydroxyacetone (DHA), and methylglyoxal (MGO). UMF™ testing is the gold standard independent quality certification for authentic manuka honey.
Manuka honey with nectar contribution from other floral sources exhibits reduced levels of the UMF™ signature compounds (leptosperin, DHA and MGO) which is proportional to the amount of non-manuka nectar incorporated into the honey. Unlike other manuka honey grading systems, such as the MGO™ based solely on MGO content and KFactor™ based on multiple non-specific manuka honey components, the UMF™ system incorporates the measurement of three key unique signature compounds for the authenticity of manuka honey. Therefore, the UMF™ certification provides assurance to consumers that the manuka honey purchased is genuine and true-to-label. Measuring only one compound, such as MGO, is not sufficient to ensure that compound is from a natural manuka honey source.