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

Here in Canada (at least Edmonton) McDonalds is serving McTwist Fries that
are  battered and spiced (not gluten free). They are on promotion for the
month of February so do not order their Fries as they to are contaminated by
the McTwist ones.  When the promotion is over, check if they have changed
the grease and cleaned the vats before ordering the regular fries.