Investigating the Antimicrobial Properties of Scottish Honey: A Citizen Science Approach

Honey and other honey bee products have been used as medical treatments throughout history. Following research carried out from the 1970s, and an ongoing and highly successful marketing campaign by the New Zealand Government, manuka honey commands a premium price due to its 'proven' medical benefits. Nearly all of these benefits are due to the strong antimicrobial activity of manuka honey, which are measured in terms of unique manuka factor (UMF).

A valuable industry has grown up around the medical benefits of manuka honey and it is the only honey currently used in human and veterinary medicine for wound healing. Wounds in humans and animals are often painful and healing may be delayed and be prone to complications, which are often due to infection. In medical and veterinary practice honey is routinely used, and dressings that contain medical-grade manuka honey have proven effectiveness for treating complicated wounds in people and animals.

Due to the high cost and limited availability of manuka honey, there is interest from vets and doctors in identifying other sources of honey for use in wound healing, which could be used in both developed and low and middle income countries (LMICs). The ability to effectively treat wounds in the estimated 100 million working horses, donkeys and mules in LMICs using cheaper or even locally produced honey would create a huge improvement in animal and human welfare and significant socioeconomic benefits.

Researchers at the Royal (Dick) School of Veterinary Studies have investigated the antimicrobial effects of a range of honey from across the world, and a surprise result was that honey produced by bees foraging on Scottish heather plants were as effective at inhibiting the growth of common wound microbes as manuka honey. A number of other studies are beginning to support this observation, and we would like to investigate a wider range of Scottish honey, sourced and tested with support from a team of citizen scientists, to confirm the potential antimicrobial activity of heather honey.

The citizen scientists involved in the project will come from beekeeping associations and secondary schools with apiaries from across Scotland, and will take part in a two-day, laboratory-based workshop at the Easter Bush Science Outreach Centre at the University of Edinburgh. We will use and compare different experimental methods to test the antimicrobial properties of honey samples from their own hives and control samples, and also analyse the moisture and pollen content of the honey samples. The results of these experiments will create a new set of data that can be used by scientists and clinicians at the University of Edinburgh to plan further citizen science and research projects.

The citizen scientists will also provide feedback on a new educational toolkit "Honey for Horses", created as part of the project to support secondary school teachers to develop investigations with their pupils into the antimicrobial properties of honey. This toolkit will be made freely available online at the end of the project for use in secondary schools.

Honey samples from citizen scientists will be cultured aerobically prior to the workshop to check for microbiological contamination. Any contaminated honey will be excluded and replacement samples obtained where possible.
Citizen scientists will be sent details of three methods for testing the antimicrobial properties of honey (honey agar assay, disc diffusion assay, well diffusion assay, all including commercial honey and sucrose solution controls) before the workshop. On workshop day 1 they will be supported by the project team to consider each method and design their experiments, ideally comparing all three methods. A commercial laboratory strain of E. coli will be used for all assays (DH5alpha).
1) Honey Agar Assay: Nutrient agar plates containing honey at a range of concentrations inoculated with bacterial suspension and incubated at 37C overnight. Presence or absence of bacterial growth recorded.
2) Disc diffusion assay: Sterile 8.2mm diameter absorbent discs soaked in a range of honey concentrations placed onto inoculated Nutrient agar plates and incubated at 37C overnight. Zones of inhibition measured around each disc.
3) Well diffusion assay: 8.2mm wells bored into the surface of inoculated agar plates and 180ul diluted honey at a range of concentrations placed in each well. Plates incubated at 37C overnight and zones of inhibition measured around each well.
Citizen scientist honey samples and controls will also be commercially tested for quality, including diastase and hydroxymethylfurfural(HMF) levels, pH and water content. Antimicrobial activity will be assessed in terms of total activity (TA) and non-peroxide activity (NPA). The pollen in all samples will be analysed to determine floral source and manuka samples will be tested for Leptosporin for authentication.
Citizen scientists will extract pollen from each honey by centrifugation and prepare microscope slides using fuchsin stain. Moisture content will be measured using a refractometer.

The project will improve the scientific literacy of the citizen science cohort, especially any beekeepers and teachers without a formal scientific background. It will also bring all participants up to date with current research into the role of honey in wound healing, honey bee health and genetic diversity and give them an opportunity to meet and interact with the scientists and clinicians involved. We anticipate that by choosing to focus on bees, an area of considerable public interest, and revealing the scientific processes required to investigate the role of honey in wound healing via the citizen science workshop and educational toolkit, we will improve public trust in and understanding of both science and scientists.

Via pairing secondary schools with local beekeeping associations and the educational toolkit, we expect to increase the sustainability of school apiaries and encourage young people to aspire to careers in science and beekeeping, in particular highlighting apprenticeship opportunities in both areas and encouraging young people from a range of backgrounds to consider these options.

The project funding will enable the addition of a citizen science strand to the existing portfolio of public engagement with research (PER) at The Roslin Institute and EBSOC, realising a long-held ambition to include participatory research in our PER activities. The experience gained by the project team research and public engagement staff will provide a blueprint for future PER projects and insight into how a citizen science approach may be incorporated into other areas of Roslin Institute research.

The only source of medical grade honey currently available is manuka honey from New Zealand. This expensive, finite and ultimately unsustainable resource cannot continue to supply the medical device (dressings) market indefinitely. As our population ages, and the prevalence of individuals with traumatic wounds and wounds associated with diseases such as type 2 diabetes increases, the demand for honey-impregnated devices, and consequently other sources of medically active honey, is only likely to increase. Assuming this project demonstrates and strengthens the findings of previous work, Scottish heather honey could be an alternative source of medical grade honey for the future. This would have significant benefits for the Scottish beekeeping industry, tourism, and for human and animal health.