# Testing oxalic acid in honey



## Fivej

For a while now I have been kicking around the idea of conducting an experiment to see how much oxalic acid is contained in honey from hives that I am treating. I was going to test two hives. Hive one was going to have a series of five to seven treatments a week apart. Hive 2 was going to receive one treatment. The reason for this is I have done a series of treatments when I have brood and I have treated with m a q s late summer and a one shot of OA in the winter. I have only contacted one Laboratory but was shocked at the price they would charge. I was quoted $2,000 for one sample. Subsequent samples would be cheaper but I didn't bother to ask how much. The lab explained to me the challenges in conducting this test. I have to admit I did not really understand most of it not being a scientist. I am going to call around to see if I can get a more reasonable price. I am posting this for informational purposes but I am curious if anyone knows why this is so expensive and complicated. The amount of oxalic acid in vegetables such as spinach and kale is readily available so it can't be that hard or expensive to test I would think. I am interested in hearing from any scientists about this. My motivation for doing this is mainly personal and curiosity and I was hopeful perhaps I could advance the knowledge of OA and it's residuals in honey. On the personal side I extracted a bunch of deep frames in the spring and got 80 lb of absolutely delicious honey that I would love to eat but it looks like I will give back to the bees this fall unless I can assure myself that it is safe to eat. I do not sell honey and would only use this for personal consumption if the test results came back low. Any scientists out there? J


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## Tim KS

It would be interesting to know, but when treating hives, I always put a piece of cardboard below the supers until after the treatment......if I treat supered hives.

However, I have pulled honey from brood boxes of deadouts that I've used for my table, and I'm still alive. :scratch:


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## Steve in PA

Check at a local university if you can. When I was at Penn State running a GC/MS "off the books" would have been easy enough. An organic chemistry prof may even welcome the opportunity for students to do real world analysis.


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## Fivej

That's a thought. Thanks Steve


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## Fivej

Tim, if I had the money I would test supers that have been blocked off too. Some feel that the bees will get the OA on/in the honey or cappings after they are unblocked. Probably do, but in any significant amount?


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## snl

There is an older study (but darn if I can put my hand on it at the moment) that basically stated that honey had basically the same amount of OA in it after treatment than prior to the treatment.


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## SuiGeneris

The cost isn't unreasonable; even a not-for-profit entity (e.g. university) wouldn't be able to do it for a whole lot less. Gas chromatography-mass spectometry is most likely the method that would be used, and since you're looking to detect something that is in (hopefully) trace amounts, this method gets pricey. Extremely high purity gasses and solvents are needed, as is a high-purity analytical standard for oxalic acid (which is needed so that they can identify the OA in the sample and quantify it accurately).

As an example, OA at sufficiently high purity (analytical standard purity) for GC/MS is ~$700/gram! Unless the lab was testing for OA frequently, they would have to purchase this.

Similarly, partial purification of OA from the honey would likely have to be performed first, in order to get it into a suitable solvent. Again, unless the company has done OA from honey before, they'd have to generate and validate that method.

It gets cheaper for subsequent samples because some of those costs are 1-time expenses (validation of the extraction process), while analytical standards are used in small amounts and therefore a little goes a long way.


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## msl

> that basically stated that honey had basically the same amount of OA in it after treatment than prior to the treatment.


yes, but the devil is in the details
when you look at the body of work as a whole, a single late fall/winter treatment dose not significantly increase the OA in the honey crop next fall
However...anything but that, such as repeated treatments or treating in the spring trends toward an increase in OA... 
there is nothing to suggest that repeated brood on OA treatments will not impact that years honey crop













RADEMACHER 2005-_ Oxalic acid for the control of varroosis in honey beecolonies – a review, _ https://www.apidologie.org/articles/apido/pdf/2006/01/M6010.pdf

The research says if you follow the label no supers, late fall and early spring treatment there is little risk.

The real question is if the added OA is a problem 
The solution to pollution is dilution if you make 10 kg of honey and you treated once, lets say 1/8 of it ends up in the supper.. so 250mg you have boosted you honey by 25mg/Kg no big thing, you treat 2 times now your at the difference between choosing a lettice or spinach salad... but 5 treatments in a row........ 5 treatments in a row 2 or 3 times. At some point there is an impact


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## gww

Fivej
There were links to four studies that did what you say you want to do in this thread that you were part of.
http://www.beesource.com/forums/sho...in-honey-producing-hive&highlight=honey+super
One more that you do yourself might be worth the money to you if you can not trust or rely on other peoples work.
Cheers
gww


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## Bee Arthur

I don't see this article posted, but it's an interesting one from Germany. Here's one of the more striking sentences: "The colonies that were treated with oxalic acid on average had a lower content of oxalic acid in honey than the non-treated colonies."

http://web.archive.org/web/20071020111620/http://www.mellifera.de/engl2.htm


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## msl

> I don't see this article posted,


lol looks like there was an atachment issue here it is








The results of 26–34 mg/kg control and 22.8–37.7 mg/kg test group are not surprising and well with in natural variability. 
OA doesn't penetrate capping.. They treated hives in late fall when the winter feed was capped and come spring there was still no OA in the feed that was protected by the cappings and as we see in the chart from my last post the oa has broken down by the time fresh nector has come in, months later 

this study does not suggest that summer treatments won't end up in summer honey when open nectar is present in large amounts, or the flow is on. It just suggests that when used as directed by the label there is no issue


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## e-spice

Since oxalic acid is found in fairly high concentrations in normal foods I am not concerned about the possibility that treating in the winter would cause a minuscule increase of it in the following summer's honey.


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## baybee

Bee Arthur said:


> I don't see this article posted, but it's an interesting one from Germany.
> ...


In that study they also say that:










Has it been even shown experimentally that OA accumulates in honey after repeated OAVs? This is just another reasonable and safe assumption without any available experimental data.


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## gww

Bay bee


> Has it been even shown experimentally that OA accumulates in honey after repeated OAVs? This is just another reasonable and safe assumption without any available experimental data.


Except for the test that were run in the now five studies to prove out the statement that you highlighted. You either have to do your own study, base your opinion on what people took the time to study or just stay away from it cause you don't trust or don't think they studied the right thing and you don't want to do it yourself.

It seems to me that several studies saying the same thing would give a person a fair sense that it does not accumulate in honey and comb and it is enough for me to feel confident but each has to decide for them selves. If you spent the money and did it yourself to your satisfaction, others would probably not be willing to rely what you did but you could satisfy your own mind on it. Myself, I know I am not willing to spend a penny on it and so I have to rely on others and what they did study or stay away completely.

Everybody could donate to randy oliver who is repeating study on this for government approval if you are willing to wait for his results. 
Cheers
gww


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## msl

time and timeing matters


> Repeated application (4 times) in autumn or winter (3% oxalic acid dihydrate, 50–80 mL depending on colony size) increased the oxalic acid content in honey after the treatment by 13 and 18 mg/kg, respectively (Floris et al., 1998; Nozal et al., 2000).
> 
> In spring (March), a single oxalic acid treatment (3%, 3–4 mL per comb side) caused a significant increase in the oxalic acid content in honey up to 62.8 mg/kg eight days after the treatment (Kruskal-Wallis-test, P < 0.05). By June, the levels in honey were back within control limits (Brødsgaard et al., 1999).





> Repeated treatments with oxalic acid dihydrate solutions from 3.5 and 6% and 50–55 mL per hive slightly increased the oxalic acid content in honey after treatment by 22 mg/kg (Floris et al., 1998) and in spring honey by 0.3 mg and 7 mg/kg, respectively (Moosbeckhofer et al., 2003; Bogdanov et al., 2002)





> Treatments in spring or summer with varying dosages led to somewhat higher oxalic acid contents in the honey after application (Liebig, 1999; Brødsgaard et al., 1999)





> Single autumn treatments using oxalic acid dihydrate (3.1 to 6%, 5 mL/bee space) were conducted in several studies. Nanetti and Stradi (1997) reported that the content of oxalic acid in the remaining winter food was not increased.,


RADEMACHER 2005- Oxalic acid for the control of varroosis in honey beecolonies 


It seems you can blast away all you want late fall and likly early spring and have little effect on your Aug harvest, do the same in july its a different story... as baybee's snip, states they are talking about spring honey, many months after the treatment, it takes time for the OA to break down and get out of the hive, and as the studys show the more OA you put in the hive, the higher level of OA the hive has. Yes its no like outher cems that are there for years and years. but nether does it vanish instantly' 

Randys work is good, but the new slow release polymer system that does OA and FA at the same time is very promising, and is sposed to be very affordably... not wood bleach cheap, but some one needs to be making money to pay for tests/epa aproval etc

take it for what its worth... witch dosent seem like much around here


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## baybee

msl said:


> time and timeing matters
> ...


Dribble or vaporization?

Has anyone shown that OA accumulates in honey after multiple OAVs? Or maybe nobody has yet bothered to show that it doesn't?


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## gww

diet is 70–80 mg and can reach up to 400–600 mg/day in a vegetarian diet (Gay et al.,1984). Poul (2003) estimated the mean dailydietary intake of oxalic acid to be 80 mg/day.An ADI (acceptable daily intake) of 0.89 mg/kgwas suggested; this corresponds to a safe dailyintake of 53.4 mg/day for a 60 kg human. TheUS Environment Protection Agency concludedthat 0.14 mg oxalic acid or oxalate/kg/day overa 24-hour-period represents the allowablehuman exposure from all sources (US EPA,1992).Assuming a daily intake of 20 g honey witha high content of 200 mg oxalic acid/kg honey,the additional consumption of oxalic acid willbe about 0.067 mg/kg b.w. for a 60 kg person(Wibbertman, 2003). The author concludedthat this would not cause a risk to human health.The theoretical oxalic acid intake in honeyfrom either treated or non-treated bee hives isnegligible when compared to the daily intakefrom other sources (Commit
From here
https://www.apidologie.org/articles/apido/pdf/2006/01/M6010.pdf

With this as a reference of what can be normal in honey.
Concentrations in honeyvary between 3.3–761.4 mg/kg (
Cheers
gww


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## gww

Baybee
Have you read all the studies that have been linked to? MSL I know you have read them and found several of them for me to read also.
Cheers
gww


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## msl

gww as I said in post 8


msl said:


> The real question is if the added OA is a problem


the OP has about 36 kg of honey to eat...at the suggested 20g a day dose of honey it would take him like 98.5 years to eat it


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## gww

msl
I knew you read it all and like I said, I would not have read half of it with out you.
Thanks
gww


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## GregB

msl said:


> ....but 5 treatments in a row........ 5 treatments in a row 2 or 3 times. At some point there is an impact


Exactly.
While spinach/chard and the like contain OA amounts to not be concerned about, brood comb honey/perga after who knows how much OA inputs are of questionable food value if not outright toxic.

So it turns out I harvest exactly that for food - brood comb honey and perga.
OA just does not belong there in my beekeeping model.

Well, looks like from above, no one is even concerned about OA accumulations in perga (especially perga for sale).


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## snl

Sorta makes you wonder about RO and shop towels. Keeping OA in the hive over an extended period of time.... with supers on. 
Most treatments of OA take place after the honey is harvested, so no real issue.


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## msl

> Most treatments of OA take place after the honey is harvested, so no real issue.


Bingo, and that is what the research shows. The people hear "OA doesn't get in honey" miss the "when used as directed by the label" part and think its open season and people advocate brood on, super on courses of 4 and 5 treatments

The shop towel study should be enlightening when its fnished


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## GregB

snl said:


> Sorta makes you wonder about RO and shop towels. Keeping OA in the hive over an extended period of time.... with supers on.
> Most treatments of OA take place after the honey is harvested, so no real issue.


I just now realized - you are advertising OA vaporizers in your signature.


> http://OxaVap.com Your source for the ProVap 110
> OA Vaporizer. The fastest vaporizer on the market!


Well...... hehehe. 
This would not be admissible in the court.


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## snl

GregV said:


> I just now realized - you are advertising OA vaporizers in your signature.


You _JUST_ got that?  Been doing it for ... years!


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## msl

he has long proven to be a stand up guy, and has helped a lot of people he didn't need to


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## GregB

snl said:


> You _JUST_ got that?  Been doing it for ... years!


Guess never paid attention (until now). 
But I am a new guy here too.


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## Fivej

GWW and others. Yes, I have read the studies you refer to. I was confused about them and asked a friend with a chemistry background to help me understand them. We concluded that the tests did not answer the question about how much residual OA can be expected in the honey treating with OAV like how I treat them and how I would like to treat them (supers on). Thus my curiosity about testing my honey. J


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## Fivej

SuiGeneris said:


> The cost isn't unreasonable; even a not-for-profit entity (e.g. university) wouldn't be able to do it for a whole lot less. Gas chromatography-mass spectometry is most likely the method that would be used, and since you're looking to detect something that is in (hopefully) trace amounts, this method gets pricey. Extremely high purity gasses and solvents are needed, as is a high-purity analytical standard for oxalic acid (which is needed so that they can identify the OA in the sample and quantify it accurately).
> 
> As an example, OA at sufficiently high purity (analytical standard purity) for GC/MS is ~$700/gram! Unless the lab was testing for OA frequently, they would have to purchase this.
> 
> Similarly, partial purification of OA from the honey would likely have to be performed first, in order to get it into a suitable solvent. Again, unless the company has done OA from honey before, they'd have to generate and validate that method.
> 
> It gets cheaper for subsequent samples because some of those costs are 1-time expenses (validation of the extraction process), while analytical standards are used in small amounts and therefore a little goes a long way.


Yes, you are absolutely correct. The chemist explained this to me and they would have to purchase equipment. Another member here Pmed me that the price was cheap.


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## jonsl

baybee said:


> In that study they also say that:
> 
> View attachment 41823
> 
> 
> 
> Has it been even shown experimentally that OA accumulates in honey after repeated OAVs? This is just another reasonable and safe assumption without any available experimental data.


I would be leery of any study that says OA is not soluable in water, since it is.


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## Trin

I might just send some honey off to one of my best friends who happens to run the food/feed/fertilizer lab for our state. If he agrees to do the testing that is. I use OAV treatments but not when supers are on. At that time I don't think it is legal in Michigan. I might ask some of the BK phd.'s at MSU about the issue.


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## Trin

I talked to my friend today. He said that the state does not test for oxalic acid in food. They just defer to FDA standards as far as allowable amounts.


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## Trin

So looking around a little got me to somewhat of an answer. The issue is that use of OA treatments require an FDA approval. That requires funding and testing and it simply hasn't been done. There is a deferral to stated allowable levels in food, but it isn't something regularly tested in many states. So it seems that bee researchers defer to federal standards because there is a stated standard, but it hasn't necessarily been studied exhaustively. Also I expect there is some fear that treatments wouldn't be easy to regulate.

Not that I have total confidence in the FDA. Standards get changed over time because new information refutes previously held positions. It's the same old problem were money influences policy. 

Sublimation into a hive coats bees and the acid re-crystallizes on them. I hardly think a cardboard insert would do much to keep it out of the honey supers unless it is left in there for a day or 2. That could easily cause other problems if the bees had no place to put nectar except for maybe in the brood nest? 

Personally, I will do what seems reasonable to me. When I get to the place where I begin to sell honey then I may have to cave to the grey area standard, unless it is carefully defined by then. 

Possibly a talk with my house representative might move the testing ball forward. In the end I expect that the allowable limit will be moved upwards. I think we could live with a rule that allows one cycle of treatments when the supers are on, at a certain dosage.


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## Absinthe

Like most acids Oxalic acid is pretty tart. Grab a handful of sheep sorrel or some shamrocks or a piece of rhubarb stalk. take a bite that is the flavor of Oxalic acid. If there were any appreciable increase in the OA content of honey I would believe you should be able to taste it. That's my opinion, and worth every penny you paid for it. 

Also, since no one can patent OA and has much opportunity to get rich from its sale, there is no one motivated to pay for all the testing necessary to determine its safety to use with supers in place. Again, just an opinion. everyone's got one..


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## Trin

"Grab a handful of sheep sorrel or some shamrocks or a piece of rhubarb stalk."

Been nibbling on them for years. The tartness help me eat some frog legs on a 3 day survival test years ago.  Added some dew berries and served up sweet and sour frog legs. Helped cover up the swamp flavor of the dang frogs.


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## Robert Holcombe

The USDA submitted the request for OA treatment of bees / mites to the EPA who approved it based on a Canadian approval under a fast-track process during the Obama administration. You ae right, there was no profit incentive and a supplier volunteered to offer it up for sale as a distributor. They have since gone out of business. Million of pounds ( a lot is made) of OA are manufactured yearly in the USA and used in farming. 

Most of Europe has an acceptance based on total acidity of the honey. The testing issue is related to "half-life" which is rather short for OA. Non-profit European studies are available - we are falling behind while focusing on money. Tidbit: OA is critical to the human digestive system the final part. 

I have no issue, anymore, with the EPA application requirements. I do not treat in the Spring or Summer as my OAV winter treatment works wonders. I remove my supers in the early Fall leaving my winter brood chamber configuration. Post removal, the bees get the final Fall foraging and move on to robbing - that's when I treat with OAV, and often, approximately 13,500 Dead Drop Count last year for 8 foraging hives. 

My two cents, all this is from memory and subject to correction, for what it's worth


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