Well, Im just stating what was said from the technical superviser from Winexpert. Here is another story from Home Vintner-
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<div ="myh3">Ask The Vintner
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Shellfish Allergy and Chitosan
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Dear Paul:
I'm a little worried about using Chitosan as a fining agent in my
wine, because I'm quite allergic to shellfish, and I understand it's a
shellfish derivative. Should I be worried?
First off – no, you shouldn't be worried – even if you have a shellfish
allergy. While it's true that Chitosan comes from shellfish – it's
actually derived from chitin, a natural polymer found in the shells of
shellfish and crustaceans. Allergic reactions come from the proteins of
the shellfish organism, and not from the shells. And, to further allay
your concerns – any residual shellfish proteins that may have been left
on these shells are completely removed, during the process of
transforming chitin – into chitosan. And remember, virtually all traces
are removed from the finished wine, after the chitosan drops out of the
must during clearing. So, the origin of chitin, the process of creating
chitosan, and the limiation of the chitosan means even those with
shellfish allergies, can use chitosan with confidence.
Now, just a refresher – chitosan acts as an all-encompassing
floculating agent in the winemaking process. It removes all solids,
including proteins and phenolics, and has proven to be an effective
clearing agent. It was originally paired with colloidal silica in the
finings process – the silica would bring the smaller, fine particles
together within the solution – and these would be swept away by the
chitosan when it was added 24 hours later. But research has shown that
a simple adjustment in the amount of chitosan means that the silica can
be omitted altogether – with no loss in the efficency of the finings.
So, clear with confidence!