I couldn't find data. None of my colleagues has answered your post so I'll take a swing at it. It appears that several chemicals are used to purify sugar cane etc into white sugar (brown sugar has molasses, too). But I couldn't find a reputable source stating how much formalin was allowed in sugar. OTOH I did find FDA's 2013 food standards on pg 17 of 21 (http://goo. Gl/11njl8).