There was an incident involving Rabban Gamliel, who was riding a donkey from Acco to Achziv, accompanied by his student Rabbi Ilai. Along the way Rabban Gamliel saw a baked good on the ground and asked his student to pick it up instead of leaving it on the ground. From this incident the scholars learned that one should not leave food on the ground but one should pick it up. One of the scholars added a restriction to this conclusion, stated in the name of Rabbi Shimon son of Yochai: One was required to raise food on the ground in the days of Rabban Gamliel, when Jewish women were righteous and did not busy themselves with sorcery of food, but in the era of Rabbi Shimon son of Yochai one should not raise food from the ground, for Jewish women had begun to practice sorcery and one must fear that the good resting on the ground has been bewitched and could endanger the person who picks it up. They also drew a distinction between a complete baked good and crumbs. Sorcery is practiced on complete baked goods so one should not raise it, but baked goods which have been crumbled or cut cannot be bewitched, so one must pick it up from the ground. The scholars asked: From the words of the prophet Ezekiel it seems that sorcery can also be practiced on bread crumbs, for it is written “And will you profane Me among My people for handfuls of barley and for pieces of bread, killing people who should not die, and keeping people alive who should not live, by your lying to My people who listen to lies?” (Ezekiel 13:19). Does this mean that they bewitched bread crumbs to cause people’s deaths? Answer: Ezekiel meant that the women would bewitch other things and in payment would receive crumbs of bread; Ezekiel did not mean that they would bewitch bread crumbs.
(Babylonian Talmud, Tractate Eiruvin 64b)