The floss I use does say non-allergenic on the bag. As I understand it, this means there should be nothing added to the material that is likely to cause an allergic reaction.
Hypo-allergenic, I think , usually means more aggresive measures were taken in manufacturing the product. As in something might have been added to treat it. I may be way off on this. What confuses the issue is there is no regulated defination for hypo-allergic. *shrug*
Bottom line, the Wal Mart product I described was recomneded to me by people who have used it for years, and I have used most of a bag. So far no issues with it. So, it should be okay.
What you need to avoid is stuff labeled as being mildew resistant, fire retardant, stain resistant, um, impervious to gunfire, that sort of thing.