Tohoros 3:8-4:1

Tohoros 3:8

If a child is found next to some dough with a piece in his hand, Rabbi Meir says that the dough is clean but the Sages say that it’s unclean because children tend to slap dough. Let’s say that dough has been pecked by chickens and there are ritually-unclean liquids in the house. If there’s enough distance between the liquids and the dough for the chickens to wipe their mouths on the ground, the dough is clean. As far as cows and dogs, if there was enough distance for the animal to lick its tongue, the dough is clean. As for other animals, if there was enough distance for their tongues to dry, the dough is clean. Rabbi Eliezer ben Yaakov considers the dough ritually clean in the case of a dog because it is a smart animal and it won’t abandon food in favor of water.

Tohoros 4:1

Let’s say that a person throws a ritually-unclean item from one place to another, such as throwing a loaf among keys or a key among loaves (and we don’t know if they touched). In such a case, the ritually-pure objects retain their presumption of purity. Rabbi Yehuda says that if a (ritually-clean) loaf was thrown among (ritually-unclean) keys, the loaf is rendered unclean but if a (ritually-unclean) key was thrown among (ritually-clean) loaves, the loaves remain clean.