שולחן ערוך יורה דעה · סימן ס״ג

English

Meat that was found spread out in the market, one goes after the majority, because a part goes after the majority of parts. If the majority of the sellers [of meat] are non-Jews, it is forbidden. And if the majority of the sellers are Jews, it is permitted. And this is the case with meat that was found in the hand of a non-Jew and it is not known from whom he purchased it. If the meat sellers are Jews, it is permitted. This is the law [according to] Torah. And the Sages already forbade all meat that is found, either at the market or in the hand of a non-Jew, even though all the sellers and all of the slaughterers are Jews. And furthermore, the one who buys meat and places it in his house and it disappears, it is forbidden [to eat it]. Rather, if there is a sign or there were recognizable rings [on the meat], and he definitely recognizes it that it is the [same meat] or it was bound and stamped, [then the meat is permitted].

English

If one hung up a container full of pieces of meat, and the container broke and the pieces fell to the earth, and one returned and found the pieces without any sign or recognizable features, it (the meat) is forbidden, because one might think that the meat that was in in the container was dragged away by a beast or vermin, and this is other meat. But if one hung it up on a nail or something like this, where it would be impossible for vermin to take it off and and put another one in its place, it is permitted. And some permit meat that was unobserved if it was found in the same place that it was left. [Comment of Rema: And the customary practice is to be lenient, in accordance with the last opinion, and even if it was in an idolater's possession, in a place where all the sellers are Israelites who sell kosher meat. And see below 118.]