Fake Honey Is Everywhere, and These Tests Can Prove It
Some studies estimate that half of commercial honey could be adulterated.
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Is your jar of honey genuine? That cartoon bee charmingly included on its label may encourage you to think the golden substance inside was produced by such hard-working, six-legged pollinators, all happily secreting sugary deliciousness in the name of nature. But, in reality, that sweet amber could well be diluted with bee-free syrup.
According to the European Commission, just under half of commercial honey sold on the continent is fraudulent. In a report published last year, the governing body found that, out of 320 products sourced from 20 countries, 147 (46%) contained suspicious adulterants such as syrup made from rice and wheat.
This proportion was significantly higher than the counterfeit rate of a similar European Union-coordinated study conducted a few years prior, which deemed 14% of analyzed samples suspicious. Rather than evidence of a growing level of fraud, however, the authors behind the 2023 report posit that their newer, improved detection methods could explain the higher rates of adulteration they observed. They even suggest that a superior technique could uncover more “fake honey” sold on supermarket shelves.
Fortunate, then, that Maria Anastasiadi isn’t developing just one superior honey test, but two.
A test of honey
“These methods have different underlying principles to other existing methods for honey authentication, and as such target different traits in honey which can be used to identify adulteration,” said Dr. Anastasiadi, a lecturer in bioinformatics at Cranfield University, UK.
Together with her research students and colleagues from the UK’s Food Standards Agency and Science, Technology Facilities Council (STFC) and Institute for Global Food Security at Queen’s University of Belfast, Anastasiadi developed two honey authenticity techniques, one that relies on Raman spectroscopy and another technique that relies on DNA barcoding.
“The first method uses a type of Raman spectroscopy called SORS [spatial offset Raman spectroscopy] where a laser beam targets the honey through the jar and records a signal arising from the interaction of the light with the molecules inside the honey matrix,” she told Technology Networks. “This signal is a unique chemical fingerprint of each honey sample.”
This SORS method was initially devised by a team at STFC’s Central Laser Facility and is more commonly used to detect abnormalities in pharmaceuticals. After putting several samples of “honey” under the technique’s laser, the Cranfield team realized the method could just as well identify the rice and sugar beet syrups that often bulk-out counterfeit honey products. And all without even opening the jars.
“We simulated adulteration by mixing pure honey with rice syrups and sugar beet syrups at various concentrations and we built an AI model which can distinguish pure from adulterated honeys and even recognize the type of syrup used,” Anastasiadi said. “This method requires a database to be built to encompass all types of different honeys so when we measure an unknown honey the model can give a reliable prediction on the honey authenticity.”
The team say the Raman method is portable and easy to implement, making it a practical screening tool for testing honey along the commercial supply chain.
The bees’ tease
Honey is one of the most counterfeited foods on the market. A substantial portion of these adulterated products come from China, according to the Honey Authenticity Network. Given that country-of-origin labeling is not required by most regulators for a product blended from elements sourced from more than one country, many shoppers will be unaware their honey is Chinese and potentially less pure than advertised.
“The second method relies on detecting DNA from the plants used to make sugar syrups, such as rice and corn,” Anastasiadi continued. “We have identified DNA barcodes which are short sequences of DNA indicative of a plant species. Then we perform amplification of this sequence using qPCR. When the presence of these barcodes exceeds certain thresholds, the honey is suspicious for adulteration.”
Anastasiadi and colleagues at the FSA and Queen’s University of Belfast trialed the DNA method on 17 honey samples collected from bee farmers around the UK and 4 samples bought from supermarkets and online retailers. The samples were then spiked with corn and rice syrups to guarantee there were some adulterants to detect.
“This is a very sensitive method able to detect adulteration with sugar syrups even at 1% level,” Anastasiadi emphasized.
DNA barcoding was first developed in the early 2000s by a team at the University of Guelph headed by Dr. Paul Hebert. Although devised with the field of taxonomy in mind, the technique was shortly adopted by the food industry and its regulators to double-check the authenticity of certain foods, particularly seafood that could masquerade as other, more expensive species. Its use to detect unsought plant material in honey is a little more novel, and Anastasiadi is keen to take the method further.
“Both methods can be modified to be applicable for many different food ingredients,” she said. “Examples include spices, coffee, olive oil, fruit juice as well as animal-based products. The DNA barcoding method for instance is already in use by the FDA [US Food and Drug Administration] for the authentication of fish and seafood species. Our research team is actively involved in further research projects to expand this methodology to other foods.”
