At what stage does everything stop going into their mouths? I will let you know when I find out okay!! But until then I am always worried about things like paint and playdough as they taste it, it gets into everything. So a safe option is making your own. I use this very easy recipe
1/2 cup flour
1/2 cup salt
1/2 cup water
Mix it all together until you get the right “feel”. Then divide it and add food coloring. It is so much cheaper than buying (especially if you have to make a LOT to keep them busy). It does keep a while if you put left overs in the fridge as well. Otherwise just chuck the left overs and make new batch when needed!