[optimal] Re: Vegetable Dye
- From: "Richard J. Kinch" <kinch@xxxxxxxxxxx>
- To: optimal@xxxxxxxxxxxxx
- Date: Sat, 10 Jul 2010 02:59:57 -0400
Sarah,
> Does anybody know why some people refer to it as a vegetable dye?
I think some of the responses to this "urban legend" are themselves
repeating legends. Here are the facts about the chemistry and
the popular characterization.
Fluorescein sodium (disodium fluorescein, not fluorescein per se) is
simply the US government-approved coloring agent D&C Yellow Number 8.
As such it is mistaken to be a "food coloring" (it is actually "D&C"
for drugs-cosmetics, not "FD&C" for food-drugs-cosmetics like Red 40),
which is in turn mistaken to be a "vegetable dye". Some people think
"food color" means the color somehow came from foods, when in fact all
the FD&C and D&C colors are synthetic. These are colorful chemicals
which the government says is OK to swallow or apply externally as an
ingredient in food, drugs, or cosmetics.
Fluorescein (proper, not disodium fluorescein) is D&C Yellow Number 7.
By the way, sodium fluorescein is what makes auto antifreeze yellow-green.
And is used to mark bulk water, such as for marine rescues, testing
leaks and drainage, and as (ahem) as a swell prank in the local fountain.
The biological red stain eosin is related, which is what was used to
color regular gasoline in bygone days.
Richard J. Kinch
http://www.truetex.com/range.htm
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