Thinking back, we did use it for some themed cooking for icing & the cake decorations probably contained artificial colourings as well
.
I'd try as hard as possible nowadays to keep things natural. Luckily there are a load more alternative things available off the shelf now!!
I'd still use them in play though ~ Playdough, painting, water & other craft work... until there was proof it could be toxically absorbed by the skin
!!
As part of policy/procedure .. proven colourant intolerances & Parental preferences were always written down on the Children's admission forms, are you allowed to specify what you'd like on these ?