White gooey stuff in baby poop

Hello there! My baby is 13 months old and i have already started with cow milk when he turned 1.

Now a days, i am noticing something white solid gooey stuff in his poop, size is almost that of a kidney bean. Today i noticed 2 of them in his poop.

What could it be? Also i am 100 % sure it is not the solid intake (like he could have swallowed corn or something) since he is still on puree form of solids (which is entirely a different story :( )

I am tensed of this white stuff in his poop.

Any idea what it could be ?