Analytica Manuka Honey Testing

Terry Cooney and Terry Braggins formed Analytica Laboratories in 2011.  Their goal was to offer analytical testing for commercial applications.  In the agricultural area, the company tests raw milk – as well as UHT, milk powder and infant formula.  Among its services, it offers a suite of tests for manuka honey that allows consumers and beekeepers to check on the authenticity, quality, safety and composition of their honey.  Regulatory requirements are currently being changed to protect New Zealand’s valuable manuka honey export sector.

Honey, especially manuka honey, has become a high value export.  In 2015 New Zealand generated around $250 million from honey exports.

But the international demand for honey has also seen a rise in batches of honey adulterated with sugar, or poor quality honey from other sources but labelled as higher value manuka honey.

In 2014, an article in the UK paper The Independent, pointed out that more Manuka honey was being consumed in the UK than New Zealand actually produced.

Since 2014, the honey industry and MPI (Ministry for Primary Industries) have been looking at ways to protect New Zealand’s reputation for honey production in the export markets.  The unique composition of manuka honey has created problems in testing, as other standard honey tests often resulted in false results.

Much of the work has come out of pioneering work done by Waikato’s biochemist Peter Molan, who is said to have revolutionised the New Zealand honey industry by identifying manuka honey’s particular properties.

All honey will inhibit the growth of bacteria to some extent because it contains hydrogen peroxide, but manuka honey keeps inhibiting bacterial growth even when the peroxide is deactivated.

Tests were initially focused on manuka’s “unique manuka factor” (or UMF).   It was originally called UMF (unique manuka factor) because no one knew what caused the extra inhibition of bacteria once the hydrogen peroxide was removed.  UMF was trademarked by UMFHA – the Unique Manuka Factor Honey Association - so the rest of the industry had to start calling it NPA, or Non-Peroxide Activity.

In 2006 scientists isolated the responsible compound which is MG – methylglyoxal.  They also showed that another compound called dihydroxyacetone (DHA ) – which is found in the nectar of the manuka flower – is a precursor to MG.   It was also proved that DHA in the honey is an indicator of the eventual level of MG as the honey is stored or matured.

The test for MG is a lot faster and more accurate than the UMF or NPA test and scientists were able to prove a correlation between the two measures so that (for example) honey with a UMF of 10 contains 263mg/kg of MG.

UMFHA's research and trademark push comes as the Ministry of Primary Industries cracks down on the manuka honey industry amid international criticism and heat from overseas regulators, including China and the UK, for greater scrutiny.

In February 2017, New Zealand papers reported that NZ Manuka honey had been pulled from the shelves of UK grocer Fortnum and Mason, after testing revealed that the honey contained low levels of a chemical compound called leptosperin. 

The leptosperin test is relatively new.  It is said to be an indicator of the “manuka-ness” of honey and gives consumers a means of knowing which honey is the genuine article.  Until the identification of leptosperin as a manuka marker there had been a division in the industry over how best to classify manuka honey - which has added to consumer confusion.

Analytica analyses a range of compounds in honey.  They can conduct a range tests including – C4 sugars, tutin, colour and conductivity – which helps determine the honey floral origin.  They also offer nectar testing – which measures the DHA and main sugars in nectar samples.  In 2014 they launched a suite of tests for Manuka honey offering a 3 in 1 test for DHA, MG and HMF.  They have developed a way to do these tests quickly and cost effectively.

Any honey types can have a 3-in-1 test and the results will give an indication of how much (if any) manuka nectar was collected by the bees when the honey was made.

Analytica Laboratories also carry out a test for leptosperin.  This has been available since 2015.  Leptosperin is the first of what could be a number of manuka specific chemical markers, which are used to identify manuka honey for authenticity.  Leptosperin is a naturally occurring chemical, found only in the nectar of leptospermum family, in which manuka belongs.

Leptosperin concentration is stable over time, and therefore measuring its concentration in honey is a good way of identifying whether the honey comes from Manuka nectar, and whether it can be labelled as manuka honey, or a manuka blend, or as a multi-floral honey.  Leptosperin concentrations have the ability to highlight cases of possible adulteration of honey.

At this stage  the Unique Manuka Factor Honey Association (UMFHA) holds the NZ license for the use of leptosperin testing in manuka honey.

Analytica has done some controlled storage testing on honey samples to better understand how DHA, MG and HMF in honey changes.  Based on this work they’ve provided a forecast of how these compounds in honey will change over time.   In general terms, the warmer the honey, the fast the chemical reactions will take place.  

Megan Grainger is the Operations Manager in the Food Division at Analytica.  Her work shows that DHA shifts to MG during storage, which has given rise to the widespread practice of storing honey after harvest to “grow” it.  The Industry is still trying to work out how best to store the honey and for how long. 

Megan has also been involved in research to test the nectar of manuka as a method of identifying plants that will contribute to higher-grade manuka honey.  Results from the research can be used to rank plants according to their DHA and leptosperin content. 

The following is from the Ministries for Primary Industries website:

There is no agreed scientific definition for monofloral mānuka honey, so this work will provide clarity about the characteristics of monofloral mānuka honey when sold as a food.  In 2014, MPI and industry developed an interim guide to meet legislative labelling requirements for mānuka honey.

Science programme update at February 2017:

• The programme has developed criteria and test methods for identifying New Zealand mānuka honey using both chemicals in the honey and DNA from mānuka pollen.
• MPI is working with commercial laboratories to ensure that when we share the science findings, they can accurately and reliably test honey for companies. While this is happening, we are taking elements of the definition through additional external, independent review. This is expected to take about 8 weeks.
• After this work, MPI will consult with the sector on how this definition will be applied through changes to the requirements for export honey.

https://www.mpi.govt.nz/growing-and-producing/bees-and-other-insects/manuka-honey/

If you have any questions or would like more information about the MPI Manuka Honey Science Programme, email manuka.honey@mpi.govt.nz