Good question Blueline.
It just came up last week in a wine forum...Chitosan is a clarifying agent in many wine kits and it sounds like KC must use it too.
The discussion on the forum said that it doesn't trigger allergies in those allergic to shellfish. I think its because its the shellfish meat that people have an allergy to, and chitosan is derived from the shell.
but, i'm not a doctor, or a lawyer, or a biologist for that matter, so take my comment with a grain of salt.
Primary: English Mild
On tap: Pale Ale, Lancelot's Wheat, English Brown Ale, Steam Beer, HoovNuts IPA
Bottled: MOAM, Braggot, Raspberry Melomel, Merlot, Apfelwein, Pyment, Sweet mead, Cabernet
Gal in 2009: 27, Gal in 2010: 34, Gal in 2011: 13, Gal in 2012: 10