Sarah’s poop is that colour when she eats blueberries. Also once she ate one of those gingerbread Elmo cookies and I almost passed out when she proclaimed that her poo was red. I also passed out until I realized that it wasn’t blood.
I know you posted this a while ago, but I just heard some info that might help- I heard that GoodStart produces purple and blue poo sometimes- so, that could be it!