Mbh 13.77.6b

As those kine, whose complexion resembled that of Amrita, began to pour milk, the froth of that milk arose and began to spread on every side, even as when the waves of a running stream dashing against one another, copious froth is produced that spreads on every side. Some of that froth fell, from the mouths of the calves that were sucking, upon the head of Mahadeva who was then sitting on the Earth. The puissant Mahadeva thereupon, filled with wrath, cast his eyes upon those kine. With that third eye of his which adorns his forehead, he seemed to burn those kine as he looked at them. Like the Sun tingeing masses of clouds with diverse colours the energy that issued from the third eye of Mahadeva produced, O monarch, diverse complexion in those kine. Those amongst them, however, which succeeded in escaping from the glance of Mahadeva by entering the region of Soma, remained of the same colour with which they were born, for no change was produced in their complexion. Seeing that Mahadeva had become exceedingly angry, Daksha, the lord of all creatures, addressed him, saying--'Thou hast, O great deity, been drenched with nectar. The milk or the froth that escapes from the mouths of calves sucking their dams is never regarded as impure remnant.[373] Chandramas, after drinking the nectar, pours it once more. It is not, however, on that account, looked upon as impure. After the same manner, the milk that these kine yield, being born of nectar, should not be regarded as impure (even though the udders have been touched by the calves with their mouths). The wind can never become impure. Fire can never become impure. Gold can never become impure. The Ocean can never become impure. The Nectar, even when drunk by the deities, can never become impure. Similarly, the milk of a cow, even when her udders are sucked by her calf, can never become impure. These kine will support all these worlds with the milk they will yield and the ghee that will be manufactured therefrom.