<<Disclaimer: Verify this information before applying it to your situation.>>

Bulk purchases of xanthan gum can be made from:
 NUTRASWEET KELCO
 2025 East Harbor Dr.
 San Diego, CA 92113-2123

 Phone: 619-595-5930
   FAX: 619-595-5935
They sell 55# bags for about $7.60/#. This is premium quality xanthan gum,
with none of the problems reported here in the past. They will supply a
chemical analysis.
I have no interest in this organization, other than as a customer.

They can also be reached through the parent company, KELCO:

        500 West Madison St. Suite 3180
        Chicago, IL 60661-2590
        Phone: 312-831-3700
          FAX: 312-831-3704

Regards, Jack, in Willits, CA