I once tried 'fondant icing' from a supermarket as a test. It contained vanilla flavouring and some kind of oil or fat (forget which, the ol' memory isn't what it was), and the bees wouldn't touch it - so it went straight in the bin.
The Baker's Fondant I now use is made from cane sugar with a few percent of glucose added as a plasticiser - and that's all. No other added ingredients - and no problems with using it.
LJ