I made two maderia sponge cakes on Monday and covered them in cling film. On Wednesday I made butter icing, filled the cakes and then covered them with icing, decorated them etc. Someone has now told me that the cake will not be fit to eat today as I should have left it to today to do the butter icing etc. I thought that if I covered the cakes with icing, it would seal in the freshness. Is this not the case? It is too late to make another one now. Please tell me it will be okay, I don't want to make people sick.