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  • Writer's picturePatrick Dawkins

Can Mānuka Honey Avoid the Tait of ‘Adulteration’?

Honey adulteration, usually through the addition of sugar syrups, is a major threat to honey producers all around the world, including Kiwi beekeepers. Recently a project by the European Union (EU) identified 46% of honey samples imported, from 21 different countries, as suspected to have been adulterated, seemingly putting a figure on just how bad the problem is. Included in the testing were five New Zealand honeys, three of which failed the EU regulations. So, is New Zealand honey part of the problem or the solution? And why does one leading scientist think our honey industry could be doing much more to help itself.

In total 320 samples were tested by the European Commission as part of their ‘From the Hives’ multi-year action into honey fraud. Of them, 147 (46%) failed to meet the requirements of the EU Honey Directive and thus were deemed “suspicious”. Those behind the investigation say, for the most part, adulteration with sugar syrup to extend the ‘honey’ was believed to be the most frequent type of fraud, but there were instances of “false origin” on labels too.

New Zealand mānuka honey is failing the EU’s AOAC C4 sugar screening test – but can they be convinced the method is not an accurate sign of adulteration? Or, will Kiwi honeys continue to fall foul of stings such as the recent From the Hives study and suffer the resulting bad publicity?

By far the most samples tested were said to originate in China or the Ukraine. Three-quarters (66 of 89 samples) of the Chinese honey was deemed suspicious, while 74 Ukraine samples were tested, with a much lower rate of 13 suspicious. All 10 United Kingdom honeys failed.

While the sample size of honey tested from New Zealand is small, with three of five failing, it’s the sort of publicity that is best avoided, says long-time exporter to the EU, John Hartnell of Hartnell and Associates.

“It would obviously be good if we didn’t appear on this list, but New Zealand sells a lot of manuka honey in to Europe and that is where the potential issue is,” Hartnell says.

The global issue of honey adulteration has been in the spotlight for a number of years now and New Zealand mānuka honey was even highlighted as having elevated C4 sugar levels in a Hong Kong Consumers Council sting as far back as 2013.

The results from the European Commission’s From the Hives project to detect suspected honey adulteration.

Therefore, Apiculture New Zealand (ApiNZ) chief executive Karin Kos says they have not been surprised to see such a study as performed by the EU.

“We are concerned if we see NZ honey pop up in a list concerning adulteration, but there are other factors at play and we shouldn’t read too much into it or draw any conclusions from it” Kos says.

Why the suspicion?

While the EU study does not offer details on where in the Honey Directive samples failed, Hartnell believes in all likelihood it will be the C4 sugars test – but in manuka honey’s case that doesn’t mean it has been adulterated. There is a long held belief in New Zealand that mānuka honey has naturally elevated levels of C4 sugars and returns ‘false positive’ results to the common C4 test, with Waikato University’s Dr Megan Grainger authoring a study in 2014 titled The Unique Manuka Effect: Why New Zealand Manuka Honey Fails the AOAC 998.12 C-4 Sugar Method.

Dr Megan Grainger. The Waikato University scientist believes the New Zealand honey industry should be doing more to try to improve the perception of mānuka honey internationally.

“My recommendation is that evidence points to the fact that there is something seemingly unique going on with mānuka honey and the current AOAC C4 method is not a good indication as to authenticity,” Grainger says.

“This survey just says they are ‘adulterated’, but I would assume they are testing C4 using the AOAC test. Those honeys would have been tested off the shelf and could be six or 12 months old. In that circumstance, we know mānuka will naturally have elevated C4 levels. Our research suggests there is a chemical rection occurring, so it will keep changing.”

Grainger, who also sits on ApiNZ’s Science, Research and Focus Group, conducted a literature review for the Ministry for Primary Industries (MPI) into understanding the relationship between mānuka honey and elevated C4 sugar levels last year. Her review suggested the New Zealand honey industry would be best served by promoting alternate testing methods for their honeys, such as chemical profiling.

“If New Zealand goes to a chemical method of testing, unless everyone around the world, including the EU, accepts it, then we are still going to get caught up in stings like this latest release,” Grainger points out though.

And C4 sugars might be the major area of concern, but New Zealand honeys, and notably mānuka, also struggle to meet standards for the enzyme diastase in the EU as well. That issue was highlighted on the world stage when nationally award-winning Kaimai Range Honey samples from New Zealand were red carded from the Apimondia World Honey Awards in 2019 (as detailed in the October 2019 issue of Apiarist’s Advocate).

Grainger is also seeking to tackle the diastase issue for New Zealand honeys with her research, and is nearing completion of a study, funded by The Experiment Company and Callaghan Innovation, she says proves that mānuka honey more readily fails diastase tests as the diastase disappears faster in mānuka than other honeys.

“It looks to be a combination of the 3-phenyllactic acid (3-PLA) in mānuka initially and then, over time, the MGO also contributes. It makes perfect sense, because MGO cross-links to proteins and, guess what enzymes such as diastase are – proteins.

“The MPI mānuka honey standard requires at least 400mg/kg of 3-PLA, but if that is driving the diastase to decrease, then what chance do we have? The international methods are flawed for New Zealand honey.”

Is there a solution?

Grainger says, at this stage, she is sceptical the likes of the EU are going to adjust their standards for “a little country at the bottom of the world who claims their honey is special”, but one exception has been made to the international food standard ‘CODEX’ to allow a citrus honey, which has a naturally low diastase.

“The C4 testing doesn’t work, the diastase testing doesn’t work, but this is just for mānuka. How are we going to convince the rest of the world that, actually, we are not bad beekeepers, there is merit to what we are saying, and they need to change their regulations to support what we see in our honey? It’s a tough one, because it is hurting our industry,” the Waikato University scientist says.

Tough it may be to overturn the regulations of a behemoth of a trade block like the EU, but if the New Zealand honey industry is to have any chance there are some things that could be done, Grainger believes.

“In these kinds of cases, we all have to be publishing. It’s no good only myself, Karyne Rogers, Merilyn Manley-Harris, Terry Braggins and Russel Frew publishing. Overseas they will think we have an agenda. It needs to be picked up by as many people, showing the same results, as possible from a large number of samples.”

One study that could assist New Zealand’s argument is research into diastase levels in New Zealand honey led by Braggins in 2020. Members of ApiNZ and the Unique Manuka Factor Honey Association helped fund that work, but it is yet to be published, limiting its credibility.

Kos says the fact that work is there provides some credibility, but the aim is to have it published. As far as more research goes, she believes, industry needs to take responsibility.

“Diastase and C4 sugars have been on the radar for a while now. They deserve some research, which requires funding, which requires an industry-wide commitment. Even getting the funding for the diastase research took quite some time and effort,” Kos says.

The ApiNZ chief executive has an ally in Grainger there too.

“I don’t think there has been enough done and, I hate to bring this up again, but we don’t have a levy to help fund this research. I am funding some of this work from my own research account,” the Waikato scientist says.

Further to that, there is more the honey industry could be doing to aid research and improve the international reputation of New Zealand honey, simply by being more open with data to assist researchers.

Honey samples awaiting diastase testing in research at Waikato University funded in large part by The Experiment Company – one of few private backers to New Zealand honey research.

“The more data from numerous beekeeping operations, the better. That starts with the big guys, who are testing every single batch and collecting harvest dates, mānuka markers to prove it’s mānuka, HMF to prove it is fresh, then the diastase levels to show how variable it is,” the scientist says.

“It is important to have a wide range of data to analyse, to determine trends. The more data points you have, the nearer to the true value you end up. I think it would then be a powerful document to show to the EU if we could pull together all the data that is out there in New Zealand.

“Right now, we are saying ‘we have a problem’. But until we get the collective might to prove it is not just a dodgy beekeeper, the EU will think the later.”

So, while the explanation of ‘false positive’ is given for three out of five New Zealand honey samples being deemed suspicious in the EU study, that cry has now been made for over 10 years without carrying weight in the international market place. That fact is something Grainger’s 2022 report to MPI makes clear.

‘Firstly, the reputation of the industry may be threatened due to the implications of media coverage when failed batches are exposed,’ the report states, adding, ‘This could have a flow on effect that impacts demand for mānuka honey overseas, and result in a decrease in the value of the honey.’


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