First published 2014

Exisle Publishing Limited,
P.O. Box 60–490, Titirangi, Auckland 0642, New Zealand.
‘Moonrising’, Narone Creek Road, Wollombi, NSW 2325, Australia.

Copyright © Cliff Van Eaton 2014

Cliff Van Eaton asserts the moral right to be identified as the author of this work.

All rights reserved. Except for short extracts for the purpose of review, no part of this book may be reproduced, stored in a retrieval system or transmitted in any form or by any means, whether electronic, mechanical, photocopying, recording or otherwise, without prior written permission from the publisher.

A catalogue record for this book is available from the National Library of New Zealand.

Print ISBN 978 1 77559 163 4
ePub ISBN 978 1 77559 200 6 Version 1.0

Disclaimer: This book is a general guide only and should never be a substitute for the skill, knowledge, and experience of a qualified medical professional dealing with the facts, circumstances and symptoms of a particular case. The author and the publisher are not responsible for any adverse effects or consequences resulting from the use of the information in this book. It is the responsibility of the reader to consult a physician or other qualified healthcare professional regarding his or her personal health. The book contains references to products that may not be available everywhere. The intent of the information provided is to be helpful; however, there is no guarantee of results associated with the information provided. Use of brand names does not imply endorsement.

Cover and text design and production by Art Rowlands



A quick introduction

1. The sample that didn’t make sense

2. You never can tell with bees

3. Giving the stuff away

4. The press release that grew legs

5. Merely a weed

6. Saved by a pot of honey

7. Let food be thy medicine

8. One from another



Select bibliography


Picture credits

To Peter Molan
An immigrant scientist and non-beekeeper who has had the greatest impact on New Zealand beekeeping since Mary Bumby arrived with the first two skeps of honey bees in 1839


In researching this project, I have been able to call on my own experiences in New Zealand as a beekeeping advisor, bee disease specialist, consultant and scientist over 30 years. I’ve been extremely fortunate to be able to watch the story of manuka honey as it has unfolded over almost that entire time, and I have even had a few direct personal experiences with the honey, both when nobody seemed to want it, and when it developed into one of the most famous (and certainly most expensive) honeys in the world.

More than that, however, I have been helped beyond measure by a number of people who have played central roles in the whole saga. In particular I want to give a special vote of thanks to Dr Peter Molan, who so kindly agreed to a very long interview, as well as provided thoughtful answers to my numerous email queries. Full of energy, ever-inquisitive, and a great communicator of often complicated science in a way that manages to excite the rest of us, Peter is undoubtedly the star of this book.

Thanks also go to the following people for agreeing to interviews: Kerry Simpson, Murray Reid, Malcolm Haines, Les Blackwell, Bill Floyd, Bill Bracks, Julie Betts, Dr Jonathan Stephens and Dr Ralf Schlothauer. They are all important characters whom you will meet in the pages to come, and the time they spent with me sharing their recollections and insights was the most rewarding part of the whole book-writing experience.

After all these years Alan Bougen remains a close personal friend, and he has been my most constant source of encouragement throughout the process of researching, composing and editing this book. My former colleague Dr Mark Goodwin kindly offered access to the archives at Ruakura Agricultural Research Centre, without doubt the most extensive source of historical beekeeping material in New Zealand. And Murray Reid, a fellow beekeeping advisor for many years, opened his ‘ark-hives’ to me as well. To all three of these great mates, cheers!

Thanks also must go to Bogdan Gan, at Kiwi Bee Ltd, for showing me the company’s extraction and processing facility for medical-grade manuka honey, the most technologically sophisticated ‘beekeeper’s shed’ I have ever seen. And kia ora to Kuini Puru of the New Zealand Historic Places Trust for coming in on her day off to take me through the mission house at Mangungu.

I am extremely grateful to Gareth St John Thomas and his team at Exisle Publishing, who have been so supportive in allowing me to write this ‘different sort of book’ on honey. Ian Watt has been a calm and steady influence during the entire book-making process, including book design and proof-reading.

Lastly, let me beg one further moment of your time to pay tribute to my dear Bonnie—best friend, life-partner, and chief cook and bottle-washer these past months. Hugs beyond measure, and kisses sweeter than honey!

A note on using this book

As I hope will become clear, this is not a scholarly book. The book does, however, contain a number of interesting facts and challenging ideas, and so a Notes section has been included at the end of the book to provide more information about the sources I have used. As well, in the text itself you will find endnote markers (1, 2, ...). This indicates that there is more information about the topic being discussed in the Notes at the end of the book.


The book you are about to read is not a comprehensive scholarly review of manuka honey, or even of honey in general. There are other publications that attempt to do the latter, not to mention the well over 2500 scientific papers just on the therapeutic properties of manuka honey alone. Those sorts of works can certainly be useful, if sometimes hard for the layman to understand. But the real problem is that, unless you are very good at reading between the lines, they leave out much of what is a very remarkable story indeed.

This book is something a bit different: a biography, but not of the usual sort. There are plenty of human characters in the pages that follow, but the subject of this biography is actually a substance, and a very extraordinary one at that. It’s a rags-to-riches tale of how a most peculiar honey became a ground-breaking medicine, along the way turning into one of the most famous honeys in the world. Not so long ago beekeepers literally gave the stuff away. Today you can find manuka honey almost everywhere, from a traditional Chinese medicine dispensary in Shanghai to a children’s burn clinic in Baghdad; and from hospital wards in Great Britain to a stylish specialty food emporium in Rome.

Manuka is a word that the great Polynesian voyagers, the Maori, gave to a plant they discovered when they first came to the islands they called Aotearoa. Hundreds of years later, when Europeans brought honey bees to that same country now known as New Zealand, the bees began producing a very different sort of honey from that plant.

The honey was hard to get out of the combs, and even harder for beekeepers to sell. But eventually an inquisitive university lecturer discovered that it had a unique property, one that had never been found in honey before. And it soon became apparent that the honey could successfully treat wounds that didn’t heal any other way. As a result, today the words manuka honey have become firmly established in the world’s vocabulary, as well-known a New Zealand icon as kiwifruit. The pages that follow tell the story of how it got that way.

This is a book intended for the general reader. In fact, anyone with even a casual curiosity about manuka honey should, I hope, enjoy it. It hasn’t been written specifically for beekeepers, although they may find something of interest, rather than instruction, in its pages. And it is hopefully free of science-based jargon. In the past I may have been a technical writer, but I know above all else that specialists who aren’t able to communicate their knowledge in a way that the rest of the world can understand aren’t really doing their job.

Instead, my intention has been to tell what is known in New Zealand as ‘a good Kiwi yarn’. It is by turns part history (natural and human), part biology, and part scientific discovery. There’s even a smattering of economics, as well as a bit of philosophy thrown in for good measure. But, above all else, this is a story of hope for the future; a piece of optimism in a world that for good reason feels saddened and sometimes even afraid about the future of a special relationship we humans have always had with those marvellous creatures, the honey bees. To learn about the good news, however, you’ll have to read the book all the way to the end!

Cliff Van Eaton
April 2014

Image A: New Zealand, the home of manuka honey.



Peter Molan had a problem. There was his job at the University of Waikato, of course, teaching students the intricacies of biochemistry, the science of the compounds and chemical processes that make up living things. As well, he had taken on quite a bit of research. He was contracted three days a week to a local diary factory, helping them work out how to extract some special substances from cow’s milk. And scientists at two of the local agricultural research institutes had also asked for his help in determining just what was responsible for a rather strange discovery they had made, namely that bull semen (of all things) was able to kill bacteria.

But while all that work certainly kept him busy, the problem concerned something else entirely. There was this small experiment, testing some local honeys against bacteria, which he had let a high-school teacher carry out in his lab over the summer holidays in January 1980 ... and one of the samples just didn’t make sense. The teacher had then gone off to a new job with the then Ministry of Agriculture. But the little mystery remained. And Peter being Peter, he just couldn’t let it go. So now he was going to have to follow his own edict, the thing he always said when students came to him with a seemingly unexpected result: ‘do the test again’.

Peter didn’t know the first thing about honey, let alone the honeys produced in New Zealand, and for a very good reason. He came from industrialised Great Britain, half a world away. The reason he had ended up in Hamilton, New Zealand, in the heart of an area called the Waikato, with some of the best pasture-based dairy land in the world, at a university with a fairly new School of Science, was the same as for many people who have come to the country over the generations—he wanted a safe, uncrowded, unspoiled place to raise a family.

A World War II baby, Peter was born in Cardiff, and spent a fair amount of his first year of life being taken in and out of a bomb shelter, since his mother’s family home was near an armaments factory, the sort of place that was a popular target for German bombing raids.

His father, who was serving with the British forces, managed a very short leave to see his first-born, before heading back for training that culminated in his being wounded when his Sherman tank was shelled on the beach during the D-Day invasion in Normandy.

Peter’s childhood was also spent in that Welsh city, a gritty harbour terminus for coal trains, no doubt made worse by the deprivation that accompanied post-war rationing throughout Britain. But while his upbringing was typically working class, it was his good fortune to go to a primary school with teachers who, as he says, ‘got their pupils’ brains working hard’. And his parents were equally supportive, not even getting angry when their energetic and inquisitive young son took their old-fashioned alarm clock to bits. As Peter says, that created an urge to find out how things worked, an urge that has never left him.

He also successfully made his way through the dreaded 11-plus exams, which streamed young people in Britain towards either manual training and the trades, or preparation for university and professional careers. He did so well in these tests, in fact, that he secured a place in the leading state grammar school in the city, an institution on a par with the fee-paying private schools that are normally the reserve of the wealthy and well-connected. It was his high-school teachers who showed him just how interesting science could be.

There followed an undergraduate degree in biochemistry at the local university (where his first child was born just before his final, third-year exams), and then a PhD in Liverpool, since the university there was offering a paying position that he could use to help support his wife and child. But when he completed his doctorate (studying the way saliva stimulated bacteria to produce acid in the mouth), he started looking for a teaching position overseas. Every week he would take out some books on different countries from the library, and one day he saw a job advertised for a lecturer at a university in the North Island of New Zealand. The pictures in the books made the country look like just the sort of place they wanted to live, especially compared with the still bombed-out parts of hard-bitten Liverpool. And so, after being accepted for the job without even an interview, Peter and his young family headed off to the Antipodes.

When he arrived at the university, the laboratory building had just been built. It was so new, in fact, that the window blinds hadn’t been installed, and he spent his first summer setting up the labs with newspapers sellotaped to the windows to keep out the heat and glare.

It was an exciting time and, while student numbers were still low, the university was keen to recruit the best and the brightest from high schools throughout the region. So an out-reach programme was started, with lecturers visiting schools to demonstrate simple experiments and interact with staff. Peter really enjoyed the challenge. Being young himself, and certainly energetic, he also had a gift of being able to explain difficult concepts in a simple and easy-to-understand way. And so he took himself off to Otorohanga College, a high school 50 kilometres south of Hamilton in a small rural servicing town.

It was on one of those outings that he met Kerry Simpson, and formed a friendship that would change his life. Kerry was also from Britain, and had come to New Zealand for much the same reason as Peter. But Kerry also had an interest (or, as he would call it, ‘a fascination’) with bees. It had started when as a child he saw a Colonel Blimp-like character in moustache and tweeds moving rather animatedly through a field with a butterfly net. Kerry couldn’t help himself: he just had to talk to the man, who turned out to be one of those wonderful gifts to the world of science that the English seem to produce in abundance—the talented (and obsessed) amateur. He was an expert in bee species, and took quite a bit of time explaining to the young boy their names and habits. After that, insects flying by were no longer just bugs to Kerry, and as time went on and he studied biology at university, he began to dream of one day having a beehive or two (and a back garden big enough to keep them in). He finally got his wish, after moving to New Zealand and eventually taking on the job as head of science at the high school in Otorohanga.

Peter and Kerry enjoyed each other’s company, and on several occasions their families socialised together. So Peter’s lab at the university was a natural choice when Kerry needed somewhere to carry out a little experiment. He had decided to become an Apicultural Advisory Officer with the Ministry of Agriculture, and his initial training was taking place nearby. He was going to trade teaching students for helping beekeepers with their problems, but before he could begin he needed to complete some sort of research project to do with honey bees. Kerry had read that honey was supposed to be antibacterial, and someone had told him that one particular variety, produced from a New Zealand native shrub called manuka, was very good for treating cuts and burns. So he thought he would test that honey, along with a couple of others (blackberry and clover) that he had collected from his own hives.

There was nothing very complicated about the experiment. In fact, the basics go back to the 1880s when Robert Koch, a German physician, discovered how to grow (or culture) bacteria on thin, circular glass dishes developed by his friend Julius Petri. As a material (or media) on which to grow the bacteria, he first tried potatoes, but eventually settled on agar, a gelatine made from a certain type of seaweed.1 Koch used these Petri dishes (or plates) to good effect, isolating a species of Bacillus bacteria (which he was able to grow on the plate as a pure culture), and then showing, to the acclaim of the world, that it was the cause of tuberculosis. The plates, the culturing methods, and the requirements needed to prove that an organism causes a disease (called ‘Koch’s Postulates’) are still in widespread use today.

Louis Pasteur had used a similar type of culturing method in the 1860s to show that heating beer, wine and milk killed the bacteria that often spoiled them (a process the world thanked him for by calling it pasteurisation). And Paul Ehrlich also employed it at the turn of the next century in developing the concept of chemotherapy for the treatment of disease, with a compound that was a remarkably effective treatment for syphilis (and in so doing coining the term ‘magic bullet’).2 But culturing bacteria was perfected by Alexander Fleming, and in fact it was an old agar plate of Staphylococcus bacteria overgrown with bread mould that led to his discovery in 1928 of the first and most famous antibiotic of all time, penicillin.3

It’s a very small world

We should now pause for a moment and say a few words about some important fellow inhabitants of this planet where we reside. Microbes are everywhere in our world. Or, as Bill Bryson puts it much more correctly in A Short History of Nearly Everything, we are just a small part of theirs.4 It sounds absurd, but when it comes to living things the tiny are a lot bigger than the rest. Those divisions of life smaller than our eyes can see make up way more of what’s around us than all the other plants and animals put together. Individually we may not be able to see them, but together microbes have four times more biomass. The reason we often don’t notice them is that so many live underground. Again, as Bryson says, if you took all of the bacteria out of the Earth’s interior and dumped them on the surface, they would cover everything to the height of a four-storey building.

Without microbes we literally wouldn’t exist. We may thank bigger organisms like plants for supplying us with some of the oxygen we breathe, but algae and other microbes produce far more. And without bacteria grabbing nitrogen from the atmosphere and turning it into organic molecules called nucleotides and amino acids, no larger creatures could survive.

As for our up-close-and-personal relationship with bacteria, while they may be single-celled organisms, on a cell-for-cell basis there are 10 times more of them on us and in us than there are human cells that make up our body. Most of them are very useful, especially in helping us digest the food we eat. But among them are also many dangerous species, ones that often cause devastating epidemics and much else. So one of the great turning points in human history has to have been when we finally worked out that ‘germs’ like bacteria could be the cause of illness. It’s something that these days we just take for granted, as if we’ve always known it was true. But amazingly we have had telephones and lights in our homes for about the same amount of time as we have known for certain that bacteria were the cause of many diseases. Before that, even the greatest minds were apt to blame ‘bad air’ for cholera, and ‘being too clean’ for the plague.5

But while disease-causing microbes are everywhere, both animals and plants are also excellent at working out ways of dealing with these intruders, using molecules produced internally, along with an array of cells and cell processes (although those activities in our own immune system can often make us feel very unwell).

We humans are also ingenuous, and so we have worked out ways of dealing to many of the microbes that might harm us by coming up with compounds that either work directly on the microbes themselves, or stimulate our immune system to work more effectively against them. And of course many of these compounds originate from nature, even though we have become very good at making them in the laboratory as well. It is in these natural compounds, however, that we get some understanding of how the immune systems of plants work against microbes, and also how those plant substances can do many of the same things when we consume them or apply them to ourselves.

Natural products have been a particularly rich source of antibiotics, yielding, for example, the penicillins (from Fleming’s bread mould) in 1940, the tetracyclines (from soil bacteria) in 1948, and the glycopeptides, including antibiotics such as vancomycin (from another soil bacteria, in 1953).

To study the effect is a fairly simple matter of putting a small amount of a known species or strain of bacteria into a sterile dish together with some nutrient for the bacteria to live on. Next you add to the plate the substance that you want to test, incubate the plate for a while, and then measure the inhibition ring (the area around the substance where the bacteria didn’t grow).

And that’s what Kerry and Peter did with honey, a plant product altered by bees that humans were using as a healing substance thousands of years before we ever figured out that bacteria caused disease. The only twist they made came about because of some reading Peter had done. Honey produces hydrogen peroxide when it is diluted, and in 1962 it was shown that this made the honey antibacterial. But Peter also found a few scientific papers that mentioned other, non-peroxide activities of some honeys. So Peter and Kerry hit on the idea of knocking out the hydrogen peroxide, using an enzyme that is present in all living organisms called catalase.

The experiment took only a couple of days, although they had to wait for the bacterial cultures to grow, and for the honey to stop the bacteria in its tracks. All three honeys created a circle of inhibition when the catalase wasn’t used. But once the hydrogen peroxide was eliminated, both the blackberry and clover honeys had no effect. The other honey, on the other hand, the one produced by bees collecting nectar from the manuka shrub, really dealt to the bacteria. As Kerry said, ‘It was only one sample, but it still had this astonishing activity. Manuka was the winner, hands down.’

Testing the weeds

Kerry Simpson didn’t think anything more about his little experiment. He recalls writing down the results in a standard school exercise book, and he can even remember drawing some graphs. But he had other things on his mind, like trying to pack as much beekeeping information into his head as he could before he went further south to take up his first position with the Ministry. Years later, when manuka honey became famous, he went looking for the notebooks again. But in his family’s numerous moves (including living in the tiny Pacific island nation of Tuvalu), the papers had been lost.6

In Peter’s case, however, it was quite the opposite. It was like that clock his parents had let him take apart as a child. He just had to figure out what was going on with that one honey. The only way to know for sure whether the test was in error was to collect a lot more samples—not just of manuka, but of a whole host of other New Zealand-produced honeys as well—and see what happened.

Luckily he had a lot of help. There was a graduate student, Kate Russell, who needed a topic for her master’s degree. And there were two technicians, Mary Smith and Kerry Allen, who helped run the labs where students did the practical work that complemented the lectures they received. They needn’t have got involved, but they were just as interested as Peter, and they had more training in the disciplines of bacterial cultures and diffusion assays (the way the bacterial inhibition created by an antibacterial substance is tested and measured). Peter was a biochemist, not a microbiologist, after all.

He also had a friend who could probably get him some honey samples. Murray Reid had helped train Kerry Simpson as a beekeeping advisor in the Ministry of Agriculture, and he was stationed nearby in Hamilton. He knew a lot of beekeepers, and also had colleagues around the country with similar contacts. So Murray put out the word, and eventually a large number of honey samples began arriving at Peter’s lab.

There was white clover ( Trifolium repens), of course, the most popular honey in the country, and the one most often produced by beekeepers, since the plant was spread throughout New Zealand’s pastures, and helped make them bountiful by fixing nitrogen into the soil. There were also a few samples of buttercup ( Ranunculus repens), a spring species associated with wet pastures, as well as a number of samples marked simply as ‘mixed pasture’, since the colour of the honey was darker than the normally very white of clover honey, and it had a slightly stronger taste as well. All sorts of species might have contributed nectar to the final honey produced by the bees, including the so-called yellow weeds like cat’s ear ( Hypochaeris radicata) that sprout up in summer once the pasture begins to dry out.

Many of the other samples came from what could quite rightly be called herbs, although in the New Zealand context they weren’t just coming from a couple of plants in someone’s garden. These were species that may originally have been brought to the country for culinary or medicinal purposes, but which liked the local environment so much that they established themselves as wild escapees, in some cases even becoming what the authorities now called ‘noxious weeds’. Among them was penny royal (Mentha pulegium), a low-growing plant that literally hides in pasture, but which gives itself away when it’s walked over since it has such a strong, minty fragrance. The honey is fairly dark and, while it is distinctive, it doesn’t taste of mint at all.

And then there was thyme (Thymus vulgaris). It is said that this famous Mediterranean herb was planted in the garden of a large farm in the South Island (called a ‘sheep station’), since it was a very nice addition to roast lamb. But the plant found the environment in a particular part of Central Otago, along the dry rocks cut into canyons by the mighty Clutha River, to be so perfect that in no time it had displaced almost every other growing thing in the area, turning the steep cliffs and high flats a wondrous purple hue in the spring. Like penny royal, the ankle-deep thyme plants give off an aroma that is almost overpowering when you walk among them. The honey, of medium amber colour, tastes—at least to some people—the way Chinese incense smells.7

Image 1

A final herb provided a further half-dozen samples of honey, but this one wasn’t a fugitive, at least not at the beginning of its existence in New Zealand. Heather ( Calluna vulgaris) is well known to anyone who has walked the Highlands of Scotland, and fondness for home is probably what led some enterprising developers (and the government, it must be said) to plant it around the base of the volcanic mountains in the central North Island of New Zealand in the early 1900s in the country’s first national park.

The heather was meant to go along with the grouse they hoped to release as part of a plan to encourage well-heeled tourists to spend a shooting holiday in these newly created Antipodean Highlands, complete with a stay in a grand house in the European tradition called The Chateau. The grouse never eventuated, although The Chateau still stands, and, while honey bees clearly love the plant (and people in Europe love the honey the bees produce from it), heather in New Zealand is now officially another noxious plant.8

Honeys like no others

Along with these introduced weeds (and for honey bees, finding what we call ‘weeds’ spread all over the countryside is their version of paradise), Peter Molan and his team also received a number of honey samples that were unique to New Zealand. Cut off from the rest of the world for tens of millions of years, the ecosystems of the North and South Islands developed a wide range of flowering trees and shrubs, many of which produced enough nectar to provide at least partially for the food needs of some species of birds. In fact, when the flowers bloomed there was so much nectar that, once European settlers arrived, the honey bees they brought with them produced large crops of a number of honey varieties, many of which had never been seen before anywhere else in the world.

Image 2

In the samples there was the dark, flavoursome honey from rewarewa ( Knightia excelsa), a tall, straight tree with reddish tubeshaped flowers common in the redeveloping forest margins in parts of the North Island. There was also tawari ( Ixerba brexioides), a unique, bushy tree with shiny green leaves and bright white flowers that grows only in a couple of select ranges around Auckland and the Bay of Plenty, and which for some reason doesn’t lend itself to planting in garden landscapes. And there was kamahi ( Weinmannia racemosa), a medium-sized forest tree that grows in both the North and South Islands, and its close cousin towai ( Weinmannia silvicola), from the northern parts of the North Island. The honey itself is of a light yellow colour, with a taste that New Zealanders have long been accustomed to since it always makes up a fair portion of what beekeepers sell as ‘bush blend’. There were even a couple of samples of honey from rata, including the forest giant Metrosideros umbellata that looms over the rain forest of the South Island’s west coast with its bright red flowers, and the far more diminutive vine rata ( Metrosideros perforata), that climbs trees in the North Island bush.

Finally, there was manuka ( Leptospermum scoparium), and with it a couple of samples of its close relative called kanuka (once named Leptospermum ericoides by the botanists, but these days now included in the Kunzeas as Kunzea ericoides). Beekeepers had a hard time selling honeys from these two species, and the honey itself was difficult to remove from the combs. It was a peculiar honey that not very many people wanted but, as Kerry found with his original single sample, it was nevertheless intriguing—and produced results that just didn’t make sense.

Hydrogen peroxide, osmosis, and sweet and sour

The many honeys Peter Molan and his team tested in the lab were diluted with water until they made up only 25% of the total solution, then droplets were put into small holes ( wells) cut into the agar in the Petri dish. The agar itself contained the bacteria Staphylococcus aureus, an organism routinely used in tests of antibacterial activity. S. aureus—or staph, as it is more commonly known—is found in both the human respiratory tract and on the skin, and is the cause of both chest infections and boils. It has an even nastier side, however, since it is very adept at developing resistance to man-made antibiotics, and creates infections in over half a million patients in American hospitals each year.

S. aureus also produces catalase, but Peter and the team added more of the enzyme to destroy any hydrogen peroxide the honey may have produced, just as Peter and Kerry had done in the original experiment.

But hydrogen peroxide isn’t the only way honey kills bacteria. It is also highly acidic, with a pH (a measure of how acid or alkaline a substance is) about the same as weak vinegar. Most bacteria prefer a pH of between 7.2 to 7.4 for optimum growth, whereas the normal range in honey is 3.2 to 4.5. In fact, it is often said that if honey wasn’t so sweet it would really be sour. And it is that sweetness which gives honey its other major ability to keep bacteria at bay.

Honey is what is called a ‘super-saturated’ sugar solution, with a moisture level that can vary, but when sealed in honey comb (or a jar) is generally below 20%. It’s ‘super’ because if we try to just dissolve sugar in water we can’t get below 36% moisture (or to put it the other way, above 64° brix, the number of grams of sugar in 100ml of solution), which is the solution’s natural equilibrium. What that means in practical terms is that when honey is exposed to the atmosphere (or bacteria) it attracts moisture to itself, trying to reach that equilibrium. It acts almost like a sponge, and literally sucks the life out microbes that are exposed to it. It’s what chemists refer to as osmosis, the passage of molecules in a liquid, through a membrane, to an area outside that isn’t as dilute, until the dilutions are equal. It’s the way water moves into and out of the cells of all living things.

Only spores of a select few species of bacteria (especially one causing a serious bee disease) and fungi (the ones that turn dilute honey into mead) with really hard protein coats can withstand this osmotic pressure, the spores waiting for a time when the sugar/water solution making up the honey becomes dilute enough that the fungi can germinate. For Peter and his tests, S. aureus proved to be a perfect organism in this regard, because it isn’t affected by either the acidity of the honey or its high sugar concentration. It can be a tough bacteria to kill.9

In these first tests, most of the honeys managed to inhibit the growth of the S. aureus on the plate, at least a bit. But the area cleared of bacterial growth was much larger for many of the manuka and kanuka samples, along with a couple of samples of penny royal and a pasture weed common in the Hawke’s Bay region called nodding thistle. Other samples of nodding thistle honey didn’t produce any activity against the bacteria, however. So that one sample of manuka honey in Kerry Simpson’s first experiment clearly wasn’t a fluke. Not every sample had the same level of activity, however, and there was the suggestion that in at least a few of the samples there was the possibility of misidentification, since all they had to go on was the name written on the container, and with it presumably the experience of the beekeeper who supplied it.

A sample of manuka was also provided by Murray Reid from his own resources. It was a little 25-gram gift jar of honey that Air New Zealand had long ago provided to its business and firstclass international passengers to spread on their in-flight toast at breakfast. Murray had kept it in a cupboard at work for years, but gave it to Peter to test thinking that it would provide a perfect control, since it wouldn’t be likely to have any antibacterial action, hydrogen peroxide-based or otherwise. The honey was almost completely black in colour, but to everyone’s surprise it had one of the highest levels of activity in the test, a result which, as we will see in a subsequent chapter of this book, only made sense years later.

More tests were then carried out on the manuka and kanuka honeys. Samples were heated to 95° Celsius for over an hour, and yet they still killed the bacteria. The honey was also diluted with water twenty-fold, and tested against a much greater variety of bacteria. Only 3 of the 12 species weren’t affected. Clearly, the antibacterial activity of the manuka and kanuka honey samples was very unusual, and also very strong.

Image 3

‘Absolutely no interest to anybody’

As any scientist will tell you, just because you find something unusual in an experiment doesn’t mean that everyone else is going to think your effort has been worthwhile. Based on this first collection of 64 honey samples from around the country, Kate Russell was at least able to write up some of the testing for her Master’s of Science thesis.10

Peter himself felt the results were sufficiently worthwhile to share with the wider world in the form of a scientific paper. However, when he submitted his first paper to the New Zealand Journal of Agricultural Research, he was shocked by the reply from the editor, which Peter remembers as stating quite bluntly ‘The topic of this paper is of absolutely no interest to anybody.’ Thankfully other journals overseas didn’t display quite such an unfortunate attitude, and two papers describing the work finally appeared in the Journal of Apicultural Research, at the time the world’s most important review of beekeeping science. The first, by Peter, Mary Smith and Murray Reid, showed that the antibacterial activity of manuka honey was significantly higher than that of clover and heather honeys, but concluded that many more samples would need to be tested to determine the relative activities of all the various honeys.11 The second, written by Peter and Kate Russell, described the nonperoxide activity (a term that would eventually be abbreviated as NPA by scientists and beekeepers alike) found in some honeys, which they concluded was not due to other factors like acidity and sugar concentration, and which was linked to floral origin.12

Work continued in the lab, as time and resources permitted, still being fitted in amidst the teaching and the dairy research. Finally in 1991 another paper was published, this time in a well-known international journal published by the Pharmaceutical Society of Great Britain. Scientists from outside the country were now beginning to take an interest in the antibacterial activities of some New Zealand honeys, and in fields in addition to apiculture (the science of beekeeping).13

A much larger number of honey samples had now been tested (345 to be exact, although 79 were not identified to floral source by the beekeepers who provided them). Of that total, 50 were stated to be manuka, and a further 20 were kanuka. Catalase was again added to the samples to remove the hydrogen peroxide. And crucially, a system that was standard to all types of antibacterial testing was employed not just to measure the inhibition ring in the bacterial culture created by the adding of honey to the test well, but also to compare the inhibition to the concentration of phenol. The system was a modification of an assay for antibacterial substances used in the New Zealand dairy industry, something Kerry Allen was quite used to, and which together with Peter she helped modify for use with honey.

10+, 15+, 20+

Phenol, otherwise known as carbolic acid, was first extracted from coal tar in the early part of the nineteenth century, and was used by Joseph Lister, beginning in 1867, in his pioneering development of antiseptic methods of surgery. Since then countless children have also come into contact with it, since it is the active ingredient in carbolic soap. In the tests of New Zealand honey, it provided the all-important comparative standard.

In the test assay, plates much larger than the old Petri dishes were used, and they were square, not round. In each plate, a total of 64 wells were punched, and honey samples were placed at random in the wells, both with and without catalase. The clear zone (the inhibition ring) was measured in millimetres using callipers.

The result was then compared with that from another plate where concentrations of phenol were put in wells, and the circle where the bacteria wouldn’t grow was measured. The higher the phenol equivalent, the stronger the antibacterial activity of the honey, since the honey created an inhibition zone similar to a higher concentration of phenol.

Non-peroxide activity was only found in samples of honey from manuka, as well as a few from viper’s bugloss, another plant introduced into the dry areas of the South Island from Australia, where it had traditionally been used as a drought-resistant species suitable for sheep. The viper’s bugloss results weren’t all that spectacular. Only four samples showed activity, and the average was equivalent to about 4% phenol (similar to the concentration that was used in some less irritating brands of that old-fashioned carbolic soap). The manuka honey, on the other hand, showed non-peroxide activity levels that were on average about four and a half times that level, with activity typically equivalent to 15–30% phenol. One sample even tested out at a whopping 58% phenol equivalent. And the use of catalase, as well as the comparisons made on the much bigger plates, showed pretty conclusively that the antibacterial activity was in many cases almost entirely caused by something in the honey other than hydrogen peroxide.

Image 4

The testing also made much clearer an observation that was perhaps apparent in the previous work, but which couldn’t be concluded with certainty because of the smaller number of samples involved: there were significant differences in nonperoxide antibacterial activity in manuka honey samples supplied by beekeepers from around the country. In fact, only about 40% showed this sort of activity.

This study, the results of which were published by Peter Molan and Kerry Allen, provided for the first time a means of measuring the non-peroxide antibacterial activity of manuka honey in a way that could readily be understood by the general public, and it would become established in the years to come as a rating system on manuka honey products sold for therapeutic products (the well-known 10+, 15+ and 20+). It was certainly needed, because it was now obvious that not all manuka honey was created equal.

But big questions still remained. What was causing these differences in activity? And, even more fundamentally (because Peter still had his parents’ alarm clock firmly fixed in his mind), what was the ‘magic ingredient’ that was so special (perhaps unique) in this one honey only really produced in New Zealand? Most of all, however, how could the discovery of this different sort of antibacterial activity, and the honey that produced it, be put to any sort of practical use?

The answers to these questions, and the way manuka honey went from a neglected food product to a mainstream medicine, is what most of the rest of this book is about. But before we begin, let’s go back to basics and learn a bit more about those fascinating and sometimes frightening creatures, the honey bees. After all, if bees hadn’t produced a food from the nectar they collected from manuka flowers, we may never have discovered what an amazing substance manuka honey truly is. It’s just another example of our species-long relationship with these remarkable insects, one that we are only just learning to fully appreciate now that it is so very much in jeopardy.