Manuka Honey Grading Standards

Posted on April 26, 2017

The complexity of bee foraging behaviour and the wide range of potential nectar source plants near an apiary site, can make initial identification of a honey type challenging. For example, bees may forage from other plant species near an apiary site even when Manuka is the most abundant flowering plant at the site.

During the last 3 years, the Ministry of Primary Industries (MPI) have been developing a new classification standard to validate the purity of Manuka honey. This has been necessary to preserve and build consumer confidence in this high valued natural product.

On 11th April 2017, MPI released a draft copy of the new classification standard. This classification standard is designed to classify Manuka honey into two grades, these being ‘Monofloral Manuka Honey’ and ‘Multifloral Manuka Honey’. Any honey that does not pass these tests cannot be labelled Manuka honey.

MPI have identified 5 chemical markers that are always present in Manuka honey, and that are stable. Some chemical markers, such as Methylglyoxal (MGO), are not stable so could not be used as a reliable marker for purity.

The 5 chemical markers are as follows:

  • 3-Phenyllactic acid (3-PLA)
  • 2’-Methoxyacetophenone (2’-MAP)
  • 2-Methoxybenzoic acid (2-MBA)
  • 4-Hydroxyphenyllactic acid  (HPA)
  • DNA from mānuka pollen (DNA)

 

From the research carried out by MPI, 74% of honey initially labelled as monofloral Manuka by suppliers was determined as monofloral Manuka after applying the new classification standard. In addition, 56% of honey initially labelled as multifloral Manuka by suppliers was determined as monofloral Manuka using the new classification standard.

Permission has been granted by MPI to use this table in this article.

MPI also tested 118 samples of honey from other countries, including 47 samples of Australian honey. None of these samples were classified as Manuka honey. It is probably true to say that some honey harvested from Manuka plants in Australia could potentially be classified into either of the 2 new grades of Manuka honey. The DNA test cannot differentiate between Leptospermum scoparium (Manuka) from New Zealand and from Australia. However the DNA test does not respond to the presence of other Leptospermum species such as Leptospermum polygalifolium (Jelly Bush), which are found in Australia.

The following table compares samples with the supplier’s identification and how these samples were graded using the new MPI classification standard.

The two new grades

Monofloral Manuka honey must contain the following minimum levels of these chemical markers:

  • 3-PLA equal or greater than 400mg/kg
  • 2’-MAP equal or greater than 1mg/kg
  • 2-MBA equal or greater than 1mg/kg
  • HPA equal or greater than 1mg/kg
  • DNA less than Cq 36 or 3fg/µL

Multifloral Manuka honey must contain the following minimum levels of these chemical markers:

  • 3-PLA equal or greater than 20mg/kg but less than 400mg/kg
  • 2’-MAP equal or greater than 1mg/kg
  • 2-MBA equal or greater than 1mg/kg
  • HPA equal or greater than 1mg/kg
  • DNA less than Cq 36 or 3fg/µL

3-Phenyllactic acid (3-PLA) is the key differentiator between Pure Manuka honey and Manuka blend honey. It may be that there is some correlation between higher levels of 3-PLA and higher Non Peroxide Activity (NPA), but this is yet to be proven.

There will be a 4 in 1 test for 3-PLA, 2’-MAP, 2-MBA, and HPA. The DNA test will be a separate tests. Two laboratories have been certified to carry out these tests, these being Analytica Laboratories and Hill Laboratories. The two tests are likely to cost around $100 per test.

The DNA test has the capability to differentiate between Manuka and pollen from other plant species, including Kanuka pollen.

Manuka honey will also need to be tested for Dihydroxyacetone (DHA), Methylglyoxal (MGO), and Hydroxymethylfurfural (HMF).

What does the new Manuka honey classification standard mean for Manuka Plantations?

The key thing to keep in mind is that the consumer still wants high NPA (UMF/MGO) Manuka honey. The new classification standard is designed to validate the purity of the honey, not the NPA level in the honey.

Pure Manuka honey of higher NPA levels will almost certainly maintain current prices and may well increase in value.

It will therefore become even more important to plant larger and more mono culture plantations of Manuka, to enable beekeepers to harvest pure Manuka honey with higher NPA levels.

It is important to plant Manuka selections that exhibit higher levels of Dihydroxyacetone (DHA) in the nectar as this is directly related to higher NPA levels in the honey.

 

It must be noted that this article contains the views of Kauri Park Nurseries and not the views of MPI or the New Zealand Government.