My youngest would have bouts of really foul smelling poos that would burn his little bum red raw and he was tested for Giardia bacteria, coeliacs, and intolerances to dairy and soy and all were negative. His Paed diagnosed him with Toddler Diarrhea which is quite common and in hindsight, DD2 had it as well, only she was toilet trained early so I didn't notice it so much. Excluding things from her diet without reason to probably isn't a great idea. If it continues, I would get her tested to see if there is a problem otherwise you are removing vital nutrients from her diet without good reason to do so. I just have to make sure that he does not eat a lot of fruit in a single day and don't let him have juice and his stools are fine.