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Though the telephone number on their label I was able to contact Hellman's.
They have informed me that their mayonaise in gf .  The vinegar is made
from corn.  They also offered to send me a list of their gf products.  I
accepted.

I was very pleased with the response that I got on the phone.  The first
person I talked to immediately knew what I was talking about and was
pleasant and helpful.