Hi Stan/All
 
Stan, you referred to a post I made earlier where I suggested using
the ELISA technique (used in medical diagnostics to detect small
amounts of certain chemicals) and asked a few questions.
 
The first was whether the ELISA would pick up corn or sugarbeet/cane
proteins after going through a bee:
 
I would suspect it should - anything that survives the proccessing
steps should be able to survive exposure to a bees stomach. This may
however bee a problem - this is where the PCR (Polymerase Chain
REaction - DNA amplification technique) might be better - the latest
SIGMA manual brags that they can amplify a product to workable
amounts from as little as five pieces of original DNA (billions of
times amplification) - if this is so it would be possible to run
diluted honey through a DNA extraction column (QUIAgen makes quite
cheap ones - here they cost about US$0.50 if one buys in bulk I
think). One would almost certainly be able to get some DNA out of
this - and I am sure one could pick up sugarcane ( it is highly
unlikely in Northern Beekeeping conditions that bees will be bringing
in any nectar from a wind pollinated sugarcane - there is almost no
concievable way, from what I know about sugarcane pollination, that
bees would bring pollen from this plant. Hence primers specific for a
specific piece of DNA in the sugarcane DNA would definitely allow for
identification of contaminant sugar.
 
I suspect that for corn it would be similar, and slightly more
problematic for beet - as it is an insect pollinated plant and may
have close relatives that are similar?
 
As for the multi-antibodies ELISA - that should not be a problem.
I gather the ELISA system was originally developed using antibodies
derived from hyper immunised goats and other similar animals. These
antibodies were actually not all identical - but the system worked.
It would concievable work as well for honey.
 
Would other proteins in nectar give rise to false positives -
probably yes - although sugarcane is very far evolutionarily from
most insect pollinated plants, as is corn, sugarbeet would be
difficult here. Once could most probably use antibodies raised agains
one of the proteins, or a pice thereof in the photosynthetic pathway
- the common difference between sugar cane and corn and the rest of
the things insects could get their sugar from is that the two grasses
are C4 plants, using a different photosynthetic pathway to the
predominantly C3 plants and CAM succulents that we derive out honey
from. The C4 pathway would have some very distinctive proteins that
antibodies could be raised against.
 
There may be a lot of potential in these concepts, both ELISA and
PCR based, I suspect PCR would be easier to get of the ground as
well as more specific. Many commercial HIV detection systems are
switching from ELISA to PCR however, which means in theory that a lot
of very expensive automated ELISA machines will be comming on the
secondhand instrument market - a factor in favour of low budget ELISA
testing of food products?
 
Keep well
 
Garth
 
Garth Cambray           Camdini Apiaries
15 Park Road
Grahamstown             Apis mellifera capensis
6139
South Africa
 
Time = Honey
 
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