Hello Hervé and all,

        I had a talk today with a specialist in the Provincial Laboratory
that analyses honey. Here is what he told me:

Plants are divided in 3 groups: the monocotyledons, the dicotyledons and the
crassulassae (pineapple is in this group)
The monocotyledons plants use 4 carbon molecules in 3 steps to build C12.
The dicotyledons plants use 3 carbon moleculkes in 4 steps to build C12.
The crassulassae are particular: they act as monocotyledon at day and
dicotyledon at night.
Note that the fabrication of sugar molecules via photosynthesis is a complex
process and that we do not understand it completely yet.

Another important thing to know is that in nature, Carbon's isotope are for
99% 12C and about 1 % 13C.
They can determine carbon's isotope weight with a precision on 7 decimals.

As for honey now. The vast majority of plants that bees forage for nectar
are dicotyledons. Hence they use C3 in 4 steps to produce C12. By
comparison, cane sugar and corn sugar come from monocotyledon plants (using
C4 in 3 steps to produce C12).

Now what do they look for in their analysis ? They measure the ratio between
13C and 12C in all the sugars present in the honey sample. There is a known
variation of this ratio naturally occuring in 100% pure honey, depending on
the different species of flowers the honey bees collect nectar from for the
US honeys. Unfortunately, the ratio for Quebec's honeys is unknown, so they
use the US charts. The variation ranges from -25 0/00 and -27 0/00 (per
thousand). This correspond to a degree of uncertainty of 13 %. It means that
by only using this method, you can't tell if exogenous sugars have been add
to honey unless you get a difference above 13% in the 13C/12C ratio. That is
to say a detection limit of 13%.

To be more accurate, when they have a result out of the -25 to -27 0/00,
they have another card in their pocket. They use carbon present in the
proteins of honey as a check value. The idea behind this is that the plants
use the same carbon molecules to produce sugars and proteins. So it has been
demonstrated that there is a known correlation between the 13C/12C ratios of
honey sugars and proteins. Again there is a natural variation wich has been
calculated at 7 %, wich means that there is a degree of uncertainty of 7%.
So if they find a difference of say 5.3% with the known correlation of sugar
and protein 13C/12C ratios, they cannot tell if exogenous sugars have been
added because it may well be because of natural variations. But if they find
a difference of 9%, they can tell with certitude that that honey contains at
least 2% and at most 9% of exogenous sugars in it ( 2% over the natural
limit of 7%).

Hoping that may help a bit,

Dr Hugo Tremblay, m.v.
Vet-RAIZO Régions 1 et 11
MAPAQ-CQIASA
1600 rue Bersimis
Chicoutimi, Qc
G7K 1H9
(418) 698-3530
fax: 698-3533

::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::
-- Visit www.honeybeeworld.com/BEE-L for rules, FAQ and  other info ---
::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::