# Will OAV contaminate capped honey?



## psm1212 (Feb 9, 2016)

LeifLiberty said:


> Will OAV contaminate capped honey?


I am not an expert, but I think you are going to get a whole lot of differing opinions on your question. I think the answer is "YES" you will get oxalic acid in your honey during OAV. OA is, of course, in your honey naturally so the debate becomes whether you have "harmed" or "damaged" your honey or in any manner made it unhealthy or unfit for consumption by humans. This is where I think you get the diverging opinions.

I think most recommendations in the US recommend that you remove your supers or place a barrier above the brood chambers and below the supers before performing OAV. In Europe, where OAV has been performed for years, my understanding is that they do not have such a concern and that OAV is performed routinely with supers in place and no barriers. 

Who is right? I have no idea.


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## FlowerPlanter (Aug 3, 2011)

>Will OAV contaminate capped honey?

No

OA is an organic acid made by many plants it's already found in honey only a few ppm. There is a study somewhere on here that shows OAV did not increase the OA already found in honey after some duration of time after treatment.


But OA approved for use in the hive is labeled that supers need to be taken off.


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## LeifLiberty (Sep 23, 2014)

Ok, I wonder why they want the supers off then. Hmm.


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## psm1212 (Feb 9, 2016)

LeifLiberty said:


> Ok, I wonder why they want the supers off then. Hmm.


I do too. I have taken mine off to treat. But that just leaves a few thousand bees in the supers that do not get the treatment. 

So . . . if OA is naturally found in honey, and any increase of OA from OAV treatment dissipates over time, and nothing I have ever read has declared that honey with elevated OA levels is toxic or harmful to humans . . . what the heck are we doing?


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## crofter (May 5, 2011)

I think it was a matter of expediency to get approval! To get approval for use on product for human consumption would have increased the timeframe and complexity of approval process. I have not heard of anyone being charged with being in contravention.


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## LeifLiberty (Sep 23, 2014)

psm1212 said:


> I do too. I have taken mine off to treat. But that just leaves a few thousand bees in the supers that do not get the treatment.
> 
> So . . . if OA is naturally found in honey, and any increase of OA from OAV treatment dissipates over time, and nothing I have ever read has declared that honey with elevated OA levels is toxic or harmful to humans . . . what the heck are we doing?


Exactly. Seems like taking off the supers would reduce treatment efficacy, and make it possible for mites to receive a non-lethal dose. (I am sure there would be elevated OA levels in the hive when the supers are returned.) I do not like the idea of having mites get repeated non-lethal does, sounds like a recipe for creating resistant mites. 

I guess I will have to search for the research papers...


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## bucksbees (May 19, 2015)

http://www.livestrong.com/article/554497-sweet-potatoes-vs-potato-oxalates/

Google search.


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## dudelt (Mar 18, 2013)

LeifLiberty said:


> Ok, I wonder why they want the supers off then. Hmm.


Supers should be off to avoid contamination. Yes, it does appear naturally in honey but the EPA is doing it's part and protecting the consumers per their request. Many consumers want to have confidence that they are getting honey, and only honey that is free of contaminates, in what they buy. If you are selling to the public, please follow the regulations. Personally, I believe it is not necessary but as previously stated, adding the requirement removed a lot of regulatory hurdles and got OA approved much quicker.


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## LeifLiberty (Sep 23, 2014)

Looks like plenty to read https://scholar.google.com/scholar?hl=en&q=Oxalic+Acid+varroa&btnG=&as_sdt=1,43&as_sdtp=


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## Groundhwg (Jan 28, 2016)

LeifLiberty said:


> Looks like plenty to read https://scholar.google.com/scholar?hl=en&q=Oxalic+Acid+varroa&btnG=&as_sdt=1,43&as_sdtp=


This "study" was done on using OAD as treatment not an OAV type of treatment. Nothing has yet shown that any increase of OA in capped honey from using OAV to treat your bees.


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## snl (Nov 20, 2009)

The EPA took the Canadian regs in total which state not to use with supers on, so they could get the use of OA rushed through. You can also state that your honey is "untreated."


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## Mike Gillmore (Feb 25, 2006)

When a hive is vaporized the acid crystals coat "everything" in the hive. Within a day or two the bees have everything scrubbed up and the acid crystals are cleaned out.

If the crystals land on capped comb they are not in contact with the honey and it will be cleaned up by the bees. If supers are left on the hive with "open" cells of honey or nectar the crystals will land directly on the exposed honey in the cells. Not sure how much that actually alters the OA content in the honey, but I think I can understand the logic behind the warning to not treat with supers on and exercise prudence with the treatments.


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## Fivej (Apr 4, 2016)

LeifLiberty said:


> Exactly. Seems like taking off the supers would reduce treatment efficacy, and make it possible for mites to receive a non-lethal dose. (I am sure there would be elevated OA levels in the hive when the supers are returned.) I do not like the idea of having mites get repeated non-lethal does, sounds like a recipe for creating resistant mites.
> 
> I guess I will have to search for the research papers...


I insert an escape board below the supers the afternoon before I treat so that all of the bees get treated. I also slide a political sign under them during treatment ala Enj so I dont have to actually physically remove them. If you have a lot of hives, it would be a hassle, but I only have two so no big deal for me. J


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## Lburou (May 13, 2012)

There is one study I've seen that follows residue in bee hives after oxalic treatments, then tested 'summer honey' for residue, finding no ill effects.

Click here. It doesn't answer the question of OA levels after treating with honey supers on, yet, it kind of says it is okay. Keep in mind they treated twice in late fall, plus some emergency treatments that could affect summer honey. You should read and judge for yourself. 

Added: Paragraph 4.5.2 Taste from the article, said:


> Treatments with oxalic acid do not cause oxalic acid residues, therefore there is absolutely no danger for a change of honey taste due to oxalic acid treatments.


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## Mike Gillmore (Feb 25, 2006)

Page 407


> .....spraying and trickling of this acid (Knuti, 1996). On the other hand, the user toxicity of the recently developed *oxalic acid sublimation treatment* (Radetzki and Bärmann,2001) *has not been evaluated*


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## Lburou (May 13, 2012)

Mike Gillmore said:


> Page 407


I take your point Mike. An Industrial Hygienist told me last month that there are now standards for exposure to OAVapors. A small amount is bad. PPE is recommended 

The authors went on to say...


> 4.5.3. Maximum residue limits In an EU regulation, formic acid and components of essential oils like thymol and menthol are defined as GRAS (Generally Recognised As Safe) substances, therefore it is not necessary to fix a MRL (EU Regulation 2796, 1995). Oxalic acid is a natural constituent of most vegetables and its content lies between 300 and 17 000 mg/kg, the highest
> content being that of parsley (Agricultural Handbook, 1984). Thus, most vegetables contain much higher amounts of oxalic acid than honey. Considering the small daily intake of honey, its contribution to the total daily intake of oxalic acid is negligible. From a nutritional point of view, oxalic acid, like formic acid, also should have a GRAS status. Moreover, no significant residues are expected after oxalic acid treatments.


With so little actual research on these subjects, I just wanted to share this article for discussion purposes. But, it makes sense to me that the dribble method adds MUCH more OA to the hive than OAV. I haven't treated using OAV with the supers on.


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## psm1212 (Feb 9, 2016)

I suppose the take away is that, while deductive reasoning may tell us that there is nothing harmful in exposing uncapped honey to OAV, this assumption has not yet been scientifically proven?

Given the length of time OAV has been used in Europe, it seems that this issue would have been studied by now.

Until it is, I will keep removing supers. Or I may do the escape board method Fivej uses.


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## Mike Gillmore (Feb 25, 2006)

There are a lot of unknowns. The testing done in this study was with dribble and spraying. Using that method of application most of the OA liquid ends up on the bees, not scattered everywhere throughout the hive. With vaporization the OA crystals coat everything inside, and this method was not tested in the study. It would be nice to see a before and after detailed study with OAV used in a hive with open cells containing honey.


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## Lburou (May 13, 2012)

psm1212 & Mike, it's hard to disagree with you.


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## Riverderwent (May 23, 2013)

psm1212 said:


> I suppose the take away is that, while deductive reasoning may tell us that there is nothing harmful in exposing uncapped honey to OAV, this assumption has not yet been scientifically proven?


Deductive reasoning is underrated. "You have confirmed in tedious places what Newton found without leaving his room." Voltaire. (Though perhaps not in this instance.)


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## viesest (Jul 13, 2016)

Mike Gillmore said:


> There are a lot of unknowns. The testing done in this study was with dribble and spraying. Using that method of application most of the OA liquid ends up on the bees, not scattered everywhere throughout the hive. With vaporization the OA crystals coat everything inside, and this method was not tested in the study. It would be nice to see a before and after detailed study with OAV used in a hive with open cells containing honey.


https://hal.archives-ouvertes.fr/hal-00892183/document

Table VI. Continued. (i.e. after 4 treatments increase is ~20 mg/kg)


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## Lburou (May 13, 2012)

viesest said:


> https://hal.archives-ouvertes.fr/hal-00892183/document
> 
> Table VI. Continued. (i.e. after 4 treatments increase is ~20 mg/kg)


Excellent viesest, it looks like oxalic levels in honey after vaporization have been studied, but clear cut rules for OAV use can't be gleaned from such sketchy data. Treating in Fall & measuring honey for OA in Spring doesn't say enough to make me comfortable vaporizing honey in supers, unless you want to wait three or four months to extract.



Hal.archives # 00892183 said:


> 4.2. Evaporation
> After treating colonies during autumn with
> the Varrox evaporator (1–5 g oxalic acid dihydrate
> crystals/tablets) the oxalic acid content of
> ...


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## viesest (Jul 13, 2016)

Lburou said:


> Treating in Fall & measuring honey for OA in Spring doesn't say enough to make me comfortable vaporizing honey in supers, unless you want to wait three or four months to extract.


Nozal at. al. 32.62 (micro)g/g 55.07 (micro)g/g *(14d after 4th tr.) * it probably means 14 days after 4th treatment.

It is not about health risk, it is about contamination. (i.e nobody wants scorched SHB in their honey)

Actually this data are for Spraying, and for Evaporation is 'no increase'.


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