Is it considered normal for a baby at 2 months old to have a liquid, f…

Is it considered normal for a baby at 2 months old to have a liquid, foamy stool with moderate amount of yellow-green color and a milky-sour smell while breastfeeding? I read that it could be due to incorrect mother's feeding, thought maybe it is because of the milk, according to our grandmothers' advice, they eat porridge, soups on milk, mainly in the first month they ate only this.