Can lactic acid bacteria be present or found in baker's yeast and pizza dough?

Answer 1

lactic acid is present in sourdough, which is the reason for the sour taste. Lactobacillus bacteria produce lactic acid as a by-product.

But with fresh yeast and fresh pizza dough... I would guess that there would be no lactic acid in the dough.. unless you introduced a source of lactobacillus to the dough - such as yogurt, buttermilk or sour cream.

There are probably baker's yeast available with Lactobacillus bacteria so you can start your own sourdough. Also, wild yeast breads usually sour due to Lactobacillus bacteria floating in the air.