Manuka honey is derived from the Leptospermum tree that is native to Australia and New Zealand. The indigenous people from both lands have been using Manuka in their traditional medicines for centuries. In recent decades, laboratory studies in both countries have identified unique properties found only in some Leptospermum species in New Zealand and Australia. Today, following extensive clinical testing in Australia, New Zealand and other countries, the unique value of Manuka has been recognised worldwide.
Manuka honey is marketed throughout the world and the activity strength can be tested for and is often shown as a strength number on the labels. For commercially competitive reasons there have been a number of symbols introduced into the market over recent years that are aimed to represent the activity strength of Manuka. Following is an explanation of the more commonly used activity indicators.
Non Peroxide Activity (NPA)
In 1981, Dr Peter Molan (MBE), who is a professor at the University of Waikato in New Zealand, was researching the peroxide activity in honeys from around the world when he found that when he deliberately destroyed the Hydrogen Peroxide Activity (HPA) in honey that only one honey was still showing strong antibacterial activity. This activity became known as Non Peroxide Antibacterial Activity (NPA). Dr Molan went on to research this activity over many years and found that it was very stable in Manuka honey and could withstand both heat and light exposure and still remain highly active and effective.
Further research by Dr Molan and his team revealed that Manuka honey with this NPA activity was very effective against many strains of bacteria including Staphylococcus Aureus and the MRSA super bug. Dr Molan’s team also found that Manuka honey produced different strengths of NPA so a test was developed to measure the strength of this activity in each batch of honey. The rating for NPA is measured as a one-to-one relationship to the phenol standard e.g. NPA 5+ Manuka honey has the same non-peroxide antibacterial activity as a 5% phenol solution. It was also discovered that honey from Leptospermum species in Australia contained NPA and this became known as Australian Manuka honey.
Note – Manuka honey containing Non Peroxide Activity (NPA) is found in both New Zealand and Australia. For the most accurate activity rating on Manuka, look for the MGO. More on that below.
Unique Manuka Factor (UMF®)
In 1995, a small New Zealand bee industry group met to discuss and investigate the best way to Trade Mark and protect the unique antibacterial activity (NPA) that Dr Molan had found in some Manuka honeys. In 1998, Dr Molan announced that a new trademark for the Unique Manuka Factor “UMF®” had been registered for licence holders to use as a quality mark for describing the strength of the NPA activity in New Zealand Manuka honey.
UMF® was historically based off of NPA activity but has recently been updated to reflect the significance of MGO, in line with leading Australian research. The MGO results from dihydroxyacetone (DHA), which occurs organically in the nectar of various Manuka flowers that grow natively in Australia.
The NPA and UMF® ratings are generated by the same type of test, but ‘Unique Manuka Factor’ (UMF®) is a trademark registered by the UMF Honey Association of New Zealand. UMF® is only available for licensed use by UMF Honey Association of New Zealand members in relation to honey originating in New Zealand.
Note -the NPA and UMF® activity number designation, which signifies the honey’s antibacterial strength, are equivalent of each other when tested by an authorised laboratory.
Methylglyoxal (MGO) – the number to look for!
More recent research has shown that one of the major components that is attributed to the unique activity in Manuka honey is methylglyoxal (MGO) and this chemical marker is now used as the key indicator of activity strength in Manuka honey. MGO is the bioactive chemical that directly relates to the antibacterial activity in the honey.
MGO is measured in parts per million (ppm) and the NPA is measured as a percentage of phenol equivalent. The UMF® Association has established an official MGO, NPA and UMF® grading system.
The approximate relationship between MGO concentration and the NPA/UMF® of Manuka honey is:
- MGO 83 = NPA/UMF® 5+
- MGO 263 = NPA/UMF® 10+
- MGO 514 = NPA/UMF® 15+
- MGO 829 = NPA/UMF® 20+
Note – Care should be taken to check the actual correlation between MGO, NPA UMF® when selecting the strength of your honey.
‘Manuka’ (Leptospermum sp.) honey containing MGO, dihydroxyacetone (DHA) and Leptosperin is found in both New Zealand and Australia. MGO refers to a chemical marker found in Manuka and is now used as the key indicator of the strength of activity in the honey.
Buyers should look for this number, in addition to the Australian Manuka Honey Association’s Mark of Authenticity when buying Manuka to ensure authenticity and bioactivity. Special care should be taken to check the actual correlation between MGO and NPA/UMF® when selecting the strength of your honey.
This article was written by Dr Ben McKee, COO of Hive + Wellness Australia and 5th generation Australian Beekeeper. Original article written 08/09/2014. Updated 07/05/2020.