Our new methodology for evaluating residues in honey offers a reliable approach to determining whether honey is fit for human consumption

By Dr. Christian Berg, Study Director at ibacon - 

The majority of our research at ibacon involves testing plant protection products and ingredients to assess their impact on the environment. However, one of the latest methodologies does assess their impact on people, evaluating residues in honey and bee products used for human consumption.

Guidance Document SANTE/11956/2016 entered into force in January this year and provides technical guidance for determining the magnitude of pesticide residues in honey and setting Maximum Residue Levels (MRL). European data requirements (EU Regulation 283/2013) demand determination of residue levels in pollen and bee products. Residues taken up by honeybees from crops at blossom could be evaluated via adapted study designs taking into account the intended use pattern of the plant protection product.

I am excited to report that, having worked on the implementation of the guideline and pilot studies testing a new methodology, this has now been adopted and the implementation of full-scale GLP ibacon MRL studies for upholding consumer protection has started.

The approach involves covering flowering plant crops with tunnels and then introducing bees. Four different field sites are chosen, with a distance of at least 10 kilometres between them.  Each site comprises one tunnel treated with the plant protection product and one, untreated, control tunnel. As standard crop Phacelia tanacetifolia is used although other crop species, such as sunflower or rapeseed are frequently requested by clients.

In a standard test, bee hives are introduced just after the application of the plant protection product and the bees start to collect nectar. The collected nectar is stored and processed inside the hive, finally being stored as ripe honey. It is sampled and analysed in our laboratory to determine the level of the active substance (if relevant metabolites) contained in the of the plant protection product.

The measured residue levels of the active substance(s) contained in the plant protection product are used to set the maximum residue level which will be applied to run the consumer risk assessments. Although the human consumption of pollen, wax, royal jelly and propolis is considered as low, sometimes additional residue data for these commodities are generated.

Our methodology allows for studies to be adapted to meet specific needs and requirements.  To be successful, they require a number of key conditions: Firstly, the field sites must be suitable and offer good conditions for plant growth and flowering. Sub-optimal conditions will not provide enough nectar for collection. The fields also need adequate irrigation - particularly during dry conditions.

Secondly, it is important that the bee colonies are selected by an experienced beekeeper ensuring that empty, drawn-out honeycombs are used and that nectar originating from the applied plants is stored. In addition, experience is needed in monitoring that the nectar from the field is used in the production of the honey. Both the nectar and honey storage on each frame of the hive are assessed twice a week. As soon as sufficient amounts of honey derived from the collected nectar are available a chemical analysis is conducted on the samples in order to quantify the amount of residues in the honey.

This ibacon semi field study offers a realistic approach in determining maximum residue levels.  While the technical guidelines do depict other approaches - such as syrup trials which tries to simulate a transfer of plant protection products from a nectar source into honey – I am personally doubtful as to whether this method mimics a realistic scenario.  It is unclear as to whether the dosage of active substances and metabolites fed to bees reflect the real-life situation and hence whether the calculation of maximum residue levels is valid. I would recommend that pre-tests are conducted and further data collected before implementing syrup trials. At the moment, I would suggest to conduct a semi-field tunnel study instead of a syrup feeding study in order to obtain reliable data for setting maximum residue levels.

Want to know more about our new methodology? Read more by clicking on the download button.