Let's be clear here.  The headline claim, that "propolis"
had some sort of effect on AFB, was clearly untrue.
Propolis had to be "extracted", concentrated, and purified.

There is no question that there are significant differences
between the final result of the "extraction" process
and the raw material that bees collect, so the only question 
here is how MUCH difference there is between actual propolis 
as used by bees and the substance used in this paper. 

My concern was underlined by one poster, who has already
seems to have jumped to the conclusion that simply taking 
propolis and adding it to bee feed has had some sort of 
positive impact on her hives.

As for the extent of the differences, Randy, who says he 
saw a pre-print of the paper, says:

>> The authors did indeed test negative controls of ethanol 
>> alone in petri dishes, and they found that ethanol alone 
>> did not display antibacterial property.

Kurt says, based upon a review of the final article:

> I only scanned the paper quickly, but I did not see any mention  
> of negative controls (treatment with 10% ethanol) for comparison.

Both statements can't be right.
I can't decide, I don't have a copy of the article handy.

Randy says:

>> they added 6% percent propolis extract (at 10% ethanol) 
>> to 1:1 sugar syrup.  By my calcs, that results in a final 
>> solution of about half a percent alcohol--roughly equivalent 
>> to  the amount in "nonalcoholic" beer.

Kurt says:

> It looks like the final concentration of ethanol is 10%. 
> I don't know how that concentration may affect bees, but 
> in typical cell culture  (more sensitive), you want to 
> keep the ethanol concentration below  0.1%.

Well, which is it - a half a percent, or ten percent?

Kurt quoted the paper:

"This extract was diluted in ethanol 96% to a 
final concentration of  10% of the extract to 
form the PEE (starting solution)."

Kurt seems to have the final word on this.  I've read 
lots of similar  ethanol extraction work, and off the 
top of my head, they work hard to get the ethanol out.
I think that they had a lot more ethanol in there than
most studies would consider prudent.

Randy went on to say:

> It appears that at least some extracts of propolis may 
> very well have activity against AFB.  

But "extracts of propolis" are VERY different compounds
from "propolis",  The ethanol certainly is one big
difference, but the process of the extraction itself
needs to be examined, as there are lots of volatiles
in resins and sap.  Now, if one were to compare the 
extractions with the "raw" resins and sap, one might 
find out how the process created this new substance
which certainly seems to not propolis

Sorry, but I'm not buying this work as reasonable.
I think we need to look at the spore stage and veg stage
in light of propolis, and ask why this "effect" is being
seen, if the actual use of propolis by bees seems to have
no effect on any stage of AFB.

> the reason that plants exude the types of resins that bees 
> collect is as a means of defense against bacteria and fungi 
> that might attack plant wounds or new growth.

The list of things that are effective controls for AFB is
very short, and I am doubting these results, given the long
history of AFB surviving nicely when directly coated by massive
amounts of propolis of various types from various sources.

> concerns about the benzaldehyde

That's actual product disparagement. I think you also accused
me of a felony there without even realizing it.  Benzaldehyde 
is something that the DEA restricts carefully, as it is one of 
the components that are used to make methamphetamine.  There's 
none readily available any more without doing tons of paperwork,
nor is there ANY benzaldehyde in ANY bee repellents sold in the USA.
I think Thorne in the UK sold benzaldehyde in little 20ml bottles
for a while in the 1990s, but even they stopped selling it, as there 
is a much less-smelly product that works just as well. 

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