Talk to Pediatrician on Black Specks In Poop

My baby is 5 months 26 days old. She is 10.5 kgs. I started semi solids at 5 months. I give her banana, rice and suji. It's been 4-5 times she had black specks in her poop. Yesterday she had banana there were black specks makes sense that could be because of banana seeds. But today she only took 3 spoons of suji (not full) and her poop had brown pieces in it. I know if something isn't digested properly it comes out in poop. But I'm not getting what is it that she isn't digesting I'm only giving her these food that I mentioned above. I'm attaching pictures