Can anyone tell me what this is ?

🦋

My daughter drinks similac advanced formula .. I noticed while she was almost done drinking that there was these little brown specs of something in her bottle ??? (Yes , her bottle was completely clean and I use nursery water) So it wouldn't have anything to do with that . Her bottle is warmed up before giving it to her .. Could it just be from the formula ? She doesn't have backwash or anything and the formula isn't bad(powder kind) I'm not extremely worried but never saw this before ..

Wondering if anyone knew .

** sorry if the picture on here shows up blurry !!! Don't know how to fix it .