About Oxalic contamination of Honey
forwarded by John Pilgrim 13th August 2020
Very early on, when Europe had varroa and we didn’t, beekeepers started to use oxalic acid either sprayed as an aqueous solution or trickled in sugar syrup solution.The spraying method fell by the wayside as being too laborious and the trickle method came to dominate. At that time it was determined that very little of this oxalic acid found its way into honey – it was just about detectable when compared with controls but was completely overwhelmed by what came from plants in the nectar the bees were gathering. Natural oxalic acid content of honey was also found to be extremely variable. It is not clear what happens to the micro-crystals that are deposited on all surfaces of the hive during vaporisation/sublimation but they cease to be active (against varroa) after quite a short time. The bees do not ingest this form of oxalic acid, like they do the syrup based solution so, again, I would think very little finds its way into the honey.
Oxalic acid is often regarded as being extremely poisonous but when you consider that it would take 15-25g of the crystals taken orally to kill you that puts it into perspective. I am not sure that that amount of table salt would do you much good. I have tried the a drop of treatment solution on the tongue and believe you me you would not get very far with that!! f you insist on injecting it straight into the bloodstream then, yes, it is very poisonous. However, it is poorly absorbed through the skin (but it can cause blisters) and woodworkers have been using it for many years to bleach wood – rubbing-in quite a strong solution using nothing more than a piece of rag. It is also used the same way to clean the hull of boats.